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Based on Terzaghi-Rendulic's axisymmetric consolidation theory, a radial consolidation coefficient calculation method is proposed, and a calculation formula is provided, followed by experimental verification. Firstly, the calculation formula of the radial consolidation coefficient was derived based on the relationship between radial consolidation degree and time factor. Then, using the GDS consolidation test system, radial drainage consolidation tests under different consolidation pressures were conducted, and displacement-time curves were obtained. Finally, the calculation method proposed in this paper was used to calculate the radial consolidation coefficient under various consolidation pressures, and the theoretical solutions were compared with experimental data. The results indicate that the computational method proposed in this paper is feasible and can accurately predict the time-dependent displacement of samples undergoing radial drainage consolidation. [ABSTRACT FROM AUTHOR]

This study presents a novel approach to determining the soil's elastic modulus (E'), a critical parameter in geotechnical engineering, by employing derivative-based methodologies and one-dimensional consolidation test results. The main challenges of traditional methods, such as triaxial CD testing, include high costs, long duration, and complexity in data collection and analysis. This new approach addresses these challenges by applying derivative calculations at a specific reference stress point (Pref), resulting in a tangent equation that accurately represents the soil's compressive behavior. Utilizing the results from one-dimensional consolidation tests not only reduces dependence on costly triaxial CD tests but also ensures high accuracy in evaluating soil mechanical properties. The findings indicate that the E' value obtained from this new method is equivalent to that from triaxial CD tests, confirming the method's feasibility and effectiveness. The unique achievement of this research is the development of a fast, cost-effective, and efficient method for determining the soil's elastic modulus, opening new research directions in the field of geotechnical engineering. [ABSTRACT FROM AUTHOR]

Peat soil exhibits significant creep deformation, and its consolidation law differs from that of soft soil. This study examines the strain characteristics of peat soils during three stages of consolidation using indoor one-dimensional creep consolidation tests. The results showed that the rebound deformation after the primary consolidation stage and the secondary consolidation stage is equivalent to the deformation seen during the primary consolidation stage, about 1.003 times. However, once the deformation stabilizes, the rebound deformation decreases to 0.32–0.85 times that of the deformation observed during the primary consolidation stage. The elastic and time-independent plastic strains of the peat soil showed two-stage linear changes with ln σ z ′ . When the load was greater than the pre-consolidation pressure, the deformation modulus increases by approximately 2.10 and 1.56 times, respectively. On this basis, this study, for the first time, defines the creep rate according to the strain rate in the tertiary consolidation stage in the strain versus the time curve ( ε z ~ t ). Based on the timeline, a one-dimensional creep consolidation model is established that can accurately predict the strain during the consolidation of the peat soil foundation. The results reveal distinct strain behaviors during each stage and improve the theoretical basis for the study of creep. [ABSTRACT FROM AUTHOR]

Soil pollution by oil hydrocarbons is one of the most important kinds of pollution. In this study, clay soil from the CL class were contaminated with gasoil synthetically in 3, 6 and 9 percent by weight, and then the soil containing 6 percent of pollution reinforced with polypropylene fibers at amounts of 0.25, 0.5, 0.75 and 1 percent by weight. According to the results in all samples, Atterberg limits were reduced compared to the base soil. By increasing the percentage of contamination from 0 to 6 percent, the liquid limit and plastic index of the contaminated samples decreased. Moreover by increasing the amount of contamination to 9 percent, these values increased. Investigation of changes trend and amount of compaction characteristics (maximum dry density and optimum moisture) of samples also showed that with soil contamination, maximum dry density and optimum moisture content, had an upward and descending trend compared to the corresponding values in base soil, respectively. According to the results, the presence of contaminant in the soil was led to a decrease of consolidation coefficient, decrease of void ratio, increase of coefficient of volume compressibility and increase of permeability coefficient. The highest rate of decrease in consolidation coefficient (equivalent to 1.7 percent) and the highest increase in permeability coefficient (equivalent to 23.01 percent) was related to the contaminated sample reinforced with 0.75 percent by weight of fibers. [ABSTRACT FROM AUTHOR]

In practical engineering, the magnitude of soil unloading rebound is closely related to the physical and mechanical properties of the soil. Therefore, there are significant differences in geological conditions among the different regions. As such, targeted research on the rebound law and calculation methods of foundation pits is needed. This article reports indoor experiments and numerical simulation methods which are used to study the trends and calculation methods of foundation pit rebound based on typical geological conditions in South China. Our findings are as follows. 1) At maximum consolidation stress ranging from 100 kPa to 400kPa, the maximum rebound rate of plain fill soil in typical soil layers is 0.0539-0.0704, the rebound rate of silty clay is 0.0373-0.0528, the rebound rate of coarse sand is 0.0296-0.0343, the rebound rate of gravelly cohesive soil is 0.0159-0.0305, the rebound rate of fully weathered granite is 0.0175-0.0344, and the rebound rate of strongly weathered granite is 0.0170-0.0379. 2) The rebound indices do not change with changes in the unloading ratio or initial consolidation stress. The rebound indices of the soil layer from top to bottom are 0.0143, 0.0119, 0.0077, 0.0096, 0.0083, and 0.0076, respectively, and a formula for calculating the rebound modulus of typical soil layers in South China was proposed. 3) The pore ratio of the soil after the end of the recompression process is lower than that which occurs after the first compression. The difference between the compression porosity ratio of the soil layer from top to bottom and the compression porosity ratio is 0.1, 0.08, 0.02, 0.06, 0.02, and 0.03, respectively. 4) The calculation of the depth of influence by the self-weight stress offset method is based on the theory of eliminating self-weight stress and unloading stress. The calculation depth is not affected by geological conditions, the formula for calculating the rebound modulus is consistent with the formula obtained from experimental research, and the calculation results are in good agreement with the numerical values. [ABSTRACT FROM AUTHOR]

Peat soil exhibits significant creep deformation, and its consolidation law differs from that of soft soil. This study examines the strain characteristics of peat soils during three stages of consolidation using indoor one-dimensional creep consolidation tests. The results showed that the rebound deformation after the primary consolidation stage and the secondary consolidation stage is equivalent to the deformation seen during the primary consolidation stage, about 1.003 times. However, once the deformation stabilizes, the rebound deformation decreases to 0.32–0.85 times that of the deformation observed during the primary consolidation stage. The elastic and time-independent plastic strains of the peat soil showed two-stage linear changes with lnσz′. When the load was greater than the pre-consolidation pressure, the deformation modulus increases by approximately 2.10 and 1.56 times, respectively. On this basis, this study, for the first time, defines the creep rate according to the strain rate in the tertiary consolidation stage in the strain versus the time curve (εz~t). Based on the timeline, a one-dimensional creep consolidation model is established that can accurately predict the strain during the consolidation of the peat soil foundation. The results reveal distinct strain behaviors during each stage and improve the theoretical basis for the study of creep.

The expansion of China's highways and railways, as well as the growing demand for them, has focused attention on the impact of traffic loads on foundation settling, uneven deformation, and ground cracking. These effects have garnered considerable research attention, with particular emphasis placed on integrating innovative materials into the soil matrix. This investigation involved loading experiments utilizing a combination of lightweight soil, expanded polystyrene (EPS), and cement. Consolidation tests assessed the extent of deformation and settlement, incorporating varying proportions of EPS and cement. The test results show that when subjected to confined conditions, the stress–strain relationship curve assumes a hyperbolic shape closely linked to the e-p curve. This shape effectively captures the unique structural characteristics exhibited by lightweight soils. As the size of the EPS particles and the applied stress increase, a corresponding rise in the strain of the specimens is observed. Simultaneously, as the strain magnitude increases, the elastic modulus experiences a decline. Additionally, it is noted that this trend further increases as the doping of the cement with EPS particles increases. When the EPS volume ratio and cement mix ratio remain constant across different specimens, there is a decrease in structural strength as the size of the EPS increases. In lightweight soil, settlement can occur rapidly, with approximately 95% of total consolidation deformation happening within a few minutes, which suggests that the settlement is instantaneous and primarily consolidation settlement. The structural strength of lightweight soil shows a negative correlation with the size of EPS, implying that larger EPS size may lead to a reduction in strength. Therefore, it is recommended to consistently use EPS beads with a diameter of 3–4 mm during construction. [ABSTRACT FROM AUTHOR]

In practical engineering, the magnitude of soil unloading rebound is closely related to the physical and mechanical properties of the soil. Therefore, there are significant differences in geological conditions among the different regions. As such, targeted research on the rebound law and calculation methods of foundation pits is needed. This article reports indoor experiments and numerical simulation methods which are used to study the trends and calculation methods of foundation pit rebound based on typical geological conditions in South China. Our findings are as follows. 1) At maximum consolidation stress ranging from 100 kPa to 400kPa, the maximum rebound rate of plain fill soil in typical soil layers is 0.0539–0.0704, the rebound rate of silty clay is 0.0373–0.0528, the rebound rate of coarse sand is 0.0296–0.0343, the rebound rate of gravelly cohesive soil is 0.0159–0.0305, the rebound rate of fully weathered granite is 0.0175–0.0344, and the rebound rate of strongly weathered granite is 0.0170–0.0379. 2) The rebound indices do not change with changes in the unloading ratio or initial consolidation stress. The rebound indices of the soil layer from top to bottom are 0.0143, 0.0119, 0.0077, 0.0096, 0.0083, and 0.0076, respectively, and a formula for calculating the rebound modulus of typical soil layers in South China was proposed. 3) The pore ratio of the soil after the end of the recompression process is lower than that which occurs after the first compression. The difference between the compression porosity ratio of the soil layer from top to bottom and the compression porosity ratio is 0.1, 0.08, 0.02, 0.06, 0.02, and 0.03, respectively. 4) The calculation of the depth of influence by the self-weight stress offset method is based on the theory of eliminating self-weight stress and unloading stress. The calculation depth is not affected by geological conditions, the formula for calculating the rebound modulus is consistent with the formula obtained from experimental research, and the calculation results are in good agreement with the numerical values.

With the increasing accumulation of rubber waste, the potential reuse of rubber fillers offers a promising solution to enhance the engineering properties of low-plasticity soils while promoting environmental sustainability. In this study, the effect of rubber waste powders (RWPs) on the consolidation and deformation properties of low-plasticity clay soil (CS) was investigated using a fully automated consolidation testing procedure for clay–rubber mixtures. The study involved adding 2% up to 30% RWPs to Tehran clay, and various parameters were evaluated through consolidation, compaction, and uniaxial strength tests. The results revealed that the consolidation volume of the mixture differed from that of the CS due to the elastic nature of the rubber wastes (RWs). To achieve higher precision, a new equation was proposed to determine the void ratio, along with modified e-log p' curves for the clay–rubber mixture. Furthermore, the addition of RWPs to the CS resulted in moderated free swelling of the soil while enhancing ductility, compression index (Cc), swelling index (Cs), and recompression index (Cr). However, it was observed that the strength and modulus of elasticity of the mixture decreased with the increase in rubber content. Considering the variations in geotechnical parameters with different rubber contents, the appropriate rubber content can be selected based on specific applications in soil and rubber mixtures, considering the required geotechnical parameters. This study highlights the potential applications of RWPs as a material in civil and geotechnical engineering projects, providing valuable insights for sustainable and eco-friendly engineering practices. [ABSTRACT FROM AUTHOR]

To describe and predict the creep deformation of Changsha red loam (including sandy soil and silty clay) in China, an empirical creep model was proposed based on a laboratory consolidation compression test. Two classical soil layers were sampled from the deep foundation pit site and fourteen samples were designed for tests under different loading conditions. Results show that the deformation process illustrates deceleration and stabilization creep with its vertical load lower than 500 kPa, while it may illustrate acceleration with its vertical load higher than 500 kPa. By analyzing the experimental results, the empirical creep model of the red loam was established. Adopting the model to predict the deformation of red loam shows the prediction curves match the actual situation, proving that the model plays a significant role in predicting the creep deformation of Changsha red loam. [ABSTRACT FROM AUTHOR]

Loess is a kind of soil that experiences a long period of deposition, and it is relatively stable under natural conditions. However, in the process of engineering construction in loess areas, the original soil structures of the loess are destroyed, inducing changes in the composition and water content in the loess. These changes may cause different environmental and engineering geologic problems. To reveal the engineering properties of disturbed losses in the Chinese Loess Plateau, the physical properties of 135 groups of disturbed loess samples in Yan'an City were analyzed statistically, and the compression properties of loess with different moisture contents and dry densities were studied by high-pressure consolidation experiments. We elucidate the compressive deformation law for perturbed solids at different moisture contents and dry densities. The experimental results show that the water content rate for the best compaction performance of the disturbed loess is 16%. The compressive deformation coefficient generally decreases with increasing dry density and water content. However, when the soil moisture is low, a small amount of water and salt is concentrated in the contact position of the powder, and the soluble salt is condensed into cement. The molecular forces between particles and the bonding forces of bound water and capillary water are larger. The soil forms a porous structure with coarse grains as the main skeleton, and the cement bonding strength is strong at the contact points of the coarse grains. As a result, the loess shows high intensity at low-water content. This results in a compression-deformation coefficient that increases with dryness density in the small load range. [ABSTRACT FROM AUTHOR]

The expansion of China’s highways and railways, as well as the growing demand for them, has focused attention on the impact of traffic loads on foundation settling, uneven deformation, and ground cracking. These effects have garnered considerable research attention, with particular emphasis placed on integrating innovative materials into the soil matrix. This investigation involved loading experiments utilizing a combination of lightweight soil, expanded polystyrene (EPS), and cement. Consolidation tests assessed the extent of deformation and settlement, incorporating varying proportions of EPS and cement. The test results show that when subjected to confined conditions, the stress–strain relationship curve assumes a hyperbolic shape closely linked to the e-p curve. This shape effectively captures the unique structural characteristics exhibited by lightweight soils. As the size of the EPS particles and the applied stress increase, a corresponding rise in the strain of the specimens is observed. Simultaneously, as the strain magnitude increases, the elastic modulus experiences a decline. Additionally, it is noted that this trend further increases as the doping of the cement with EPS particles increases. When the EPS volume ratio and cement mix ratio remain constant across different specimens, there is a decrease in structural strength as the size of the EPS increases. In lightweight soil, settlement can occur rapidly, with approximately 95% of total consolidation deformation happening within a few minutes, which suggests that the settlement is instantaneous and primarily consolidation settlement. The structural strength of lightweight soil shows a negative correlation with the size of EPS, implying that larger EPS size may lead to a reduction in strength. Therefore, it is recommended to consistently use EPS beads with a diameter of 3–4 mm during construction.

In any geotechnical design, knowing the magnitude of the compression of the loaded soil layer is essential. This can be achieved by determining the value of the compression index (Cc) as well as the swell index (Cs). To obtain these parameters, a routine one-dimensional consolidation test should be conducted. Conventionally, Cc and Cs can be evaluated from the obtained e-log p curve. This is a time-consuming process hence prediction of these values is considered as an excellent alternative approach especially for preliminary assessment purposes. Although many Cc and Cs prediction models have been developed, the level of uncertainty of these models is not available. Therefore, performing research studies are still necessary to develop and/or improve the accuracy of existing models. The present experimental study on remolded soils collected from 19 sites in different parts of Mosul city/Iraq introduced a new parameter, which is the area under the consolidation and rebound curves, and it is linked to the consolidation parameters to develop a compressibility prediction model. The model results have been compared with the actual Cc and Cs values, as determined by laboratory tests, and statistically, it is found to be in good agreement. Interestingly, it has been observed that the ratio of the areas under the rebound to the areas under the consolidation curves is 0.167, which equals approximately the ratio reported in literature between Cs to Cc. The new models have been evaluated by comparing the models with better well-known correlations that have been reported by different investigators. A validation test was conducted on the proposed models to test the efficiency and the accuracy by using independent data collected from literatures. Finally, it is concluded that the new proposed models adopting areas under the consolidation and rebound curves can be used reliably to predict the Cc and Cs, respectively. [ABSTRACT FROM AUTHOR]

Xu, H.; Rui, X.; Wang, Z.; Qiu, Z.; Cai, L.; Zhang, Z., and Zhao, M., 2022. The effects of physical properties on the compression modulus of coastal fully-weathered red sandstone: Consolidation compressibility and the settlement calculation of foundation. Journal of Coastal Research, 38(4), 870–884. Coconut Creek (Florida), ISSN 0749-0208. The compressibility of rock and soil can be characterized by compression modulus, which is influenced by multiple physical properties, so it is difficult to be quickly and accurately measured on-site; thus, comprehensive exploration of their influence on the compression modulus is significant. In this paper, the physical properties of water content, fines content, and relative compaction, which can be easily measured on-site, were selected. Based on the orthogonal combination consolidation test, the variation of compression modulus of fully weathered red sandstone was investigated. Then, the relationship between compression modulus and the combination of physical properties was learned using the decision tree algorithm model for the first time, which can perform accurate and real-time prediction. The results showed that the cubic and quaternary polynomials can accurately represent the variation of compression modulus with a single physical property, and the model based on a 10-level decision tree algorithm can learn the coupling relationship between compression modulus and combination of physical properties to accurately calculate and predict the compression modulus. The algorithm model can be further applied to calculate the settlement of foundation in fully weathered red sandstone stratum with different water content during the precipitation process, which can effectively guide the engineering construction. This research provides a reference for the study of consolidation compressibility of fully weathered red sandstone and similar stratum, as well as the settlement calculation of foundation. [ABSTRACT FROM AUTHOR]

The paper presents a method of application of an ANN (Artificial Neural Network) to predict the permeability coefficient k in sandy soils: FSa, MSa, CSa. To develop an ANN the results of permeability coefficients from pumping and consolidation tests were applied. The proposed ANN with an architecture 6-8-1 predicts the value of permeability coefficient k based on the following parameters: soil type, relative density ID, void ratio e and effective soil diameter d10. The mean relative error and single maximum value of the relative error for the proposed ANN are following: Mean RE = ±4%, Max RE = 7.59%. The use of the ANN to predict the soil permeability coefficient allows the reduction of the costs and time needed to conduct laboratory or field tests to determine this parameter. [ABSTRACT FROM AUTHOR]

To describe and predict the creep deformation of Changsha red loam (including sandy soil and silty clay) in China, an empirical creep model was proposed based on a laboratory consolidation compression test. Two classical soil layers were sampled from the deep foundation pit site and fourteen samples were designed for tests under different loading conditions. Results show that the deformation process illustrates deceleration and stabilization creep with its vertical load lower than 500 kPa, while it may illustrate acceleration with its vertical load higher than 500 kPa. By analyzing the experimental results, the empirical creep model of the red loam was established. Adopting the model to predict the deformation of red loam shows the prediction curves match the actual situation, proving that the model plays a significant role in predicting the creep deformation of Changsha red loam.

ABSTRACT The pre-consolidation pressure is a soil parameter indicating the maximum load that can be supported without irreversible deformation. However, the commercially available equipment for such determination is very expensive, limiting studies on this subject. The objective of this study was to develop a low-cost press model for determining a soil pre-consolidation pressure. The press comprised an electric jack for lifting a soil sample against a fixed piston. A compression cell was built using Technyl®. The stability and smoothness of the applied loads were controlled using springs with different dimensions and strengths. The load and deformation data were obtained using an indicator connected to the load cell and a dial indicator, respectively. The equipment was tested by determining the pre-consolidation pressure in an Oxisol cultivated with cotton and under an area of native Cerrado. The pre-consolidation pressures for a soil water tension of 10 kPa were 50.8 kPa and 61.1 kPa for the soil under the native Cerrado and cotton crop, respectively, and the compressibility indexes were 0.71 and 0.37, respectively. The main advantages of this equipment are its low cost, ease of construction, and simplicity of operation. However, the equipment is non-automatic; thus, the data necessary for the construction of the compression curve must be collected by an operator.

The paper aims to comparison the permeability coefficient in non-cohesive soils by the method of test pumping and based on tests in a consolidometer. The tests were carried out on 18 types of non-cohesive soils with different fraction. Pumping tests were carried out according to the standard method i.e. by making one well with a diameter of 400 mm and installing two piezometers at different distances from the well. The water table change was measured in piezometers during water pumping from the well. Tests in the consolidometer were carried out on soil samples that were first compacted to the same density index as in the test site. The tests were carried out with a continuous inflow of water from below with constant gradients of 0.50. The tests presented in the paper allow to verify and compare the values of the permeability coefficient in non-cohesive soils determined in the field and laboratory tests.

The compression index (Cc), which is used to calculate the consolidation settlement of fine-grained soils, can be determined through consolidation testing. Given that exploring the soil in a local region is highly important to determine the correlation between the Cc and other soil indices, the present study investigated these correlations in undisturbed and disturbed samples through 130 consolidation tests and determining the Cc of Tehran clay. The results are suggestive of the validity of the linear correlation between the Cc and the unit weight and initial void ratio of the soil, with several relations presented to estimate the Cc of Tehran clay soil. In contrast, the initial water content, liquid limit and the plasticity index do not produce reliable correlations with the Cc of the local clay soil, and a relation based on these index parameters cannot be recommended in this area. Further, the presented empirical correlations were compared with the existing ones. More over time-displacement and e-log σ' graphs for undisturbed and disturbed samples are compared and stress history of the site are presented. The results are significant in terms of engineering applications, saving time and money and provides an initial estimation of compression index. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering Geology / Gongcheng Dizhi Xuebao is the property of Journal of Engineering Geology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

It is of great interest to describe and quantify the evolution of microstructure for a better understanding of rock deformation processes. In this study, 2D microstructure images of salt rock are analyzed at several stages of consolidation tests and cyclic compression tests to quantify the evolution of the magnitude and orientation of solidity, coordination, local solid volume fraction, and crack volume. In both the consolidation and the cyclic compression tests, the deformation of aggregates achieved by grain rearrangement is greater than that achieved by the deformation of an individual grain. In the consolidation test, the aggregates are rearranged into horizontal layers of coordinated grains, the orientation distribution of grain indentations is quasi-uniform, and the size of the pores reduces and becomes more uniformly distributed. As a result, salt rock microstructure becomes more homogeneous. The increase in local solid volume fraction in the lateral direction is correlated with an increase in the oedometer modulus. In the cyclic compression tests, grain-to-grain contact areas decrease due to the redistribution of grains and the propagation of intergranular cracks. Aggregates are reorganized into columns of coordinated grains. Intergranular opening-mode cracks tend to develop in the axial direction, while intergranular shear-mode cracks propagate preferentially in the lateral direction. The lateral components of the fabric tensors of coordination and local solid volume fraction decrease, which result in an increase in the Poisson's ratio. The fabric descriptors used in this work allow a better quantification and understanding of halite deformation processes and can be used in other types of rocks encountering similar deformation mechanisms. [ABSTRACT FROM AUTHOR]

Consolidation coefficient (Cv) is one of the key parameters in calculation of soil settlement rate. This parameter can be determined using one-Dimensional consolidation test. Prediction of Cv in fine- graded soils with different Liquid Limit (LL) and Plasticity Index (PI) is also substantial to have a better understanding of soil behavior. In the present study, two fine-graded soils encompassing a broad range of liquid (LL) and plastic limits (PL) are selected and conventional consolidation tests are conducted on these samples. The samples are tested using their natural water content. It was observed that increasing liquid limit and plasticity index decreases Cv.

In order to study the influence of moisture content and dry-wet cycle on the deformation characteristics of undisturbed loess, this paper carries out analysis by combining laboratory consolidation tests with theoretical methods. The result of research shows that: Under the same vertical compressive stress, the strain of undisturbed loess increases with the increase of water content, while the secant modulus decreases with the increase of water content; with the increase of vertical compressive stress, both the strain and secant modulus of the loess with the same moisture content increase, but the change rate slows down gradually. The secant modulus of the loess decreases with the increase of the number of dry-wet cycles, and the variation amplitude is large for 1～3 cycles, and small for 3～5 cycles and tends to be stable. Based on research conclusions, the stress-strain relationship models of loess with different moisture content and the secant line modulus models of loess affected by the dry-wet cycle are established. [ABSTRACT FROM AUTHOR]

A large amount of coal fly ash produced in thermal power plants is disposed of in landfills which causes many environmental problems. The utilization of fly ash can be encouraged in geotechnical engineering projects. In this paper, the effects of class C and class F fly ash on the mechanical and microstructural behavior and stabilization of clay soil were evaluated through a program of laboratory experiments. The experiments included compaction, unconfined compressive strength, consolidated-undrained triaxial, one-dimensional consolidation tests, and scanning electron microscopy analysis on samples of fly ash-stabilized clay soil after 1, 7, and 28 days of curing. The tests were conducted on mixtures of clay with class C or class F fly ash, ranging from 0% to 30% of the soil. Experimental results showed that the strength parameters and permeability of the stabilized soil improved while the compression and swelling indices decreased by the addition of fly ash and by the increase of curing days. The results obtained from the mechanical tests agreed with the results from the SEM analysis. Based on the results, the soil could be successfully stabilized by using class C fly ash. The improvements in strength, swelling, and permeability parameters of the stabilized soil were higher with the class C fly ash compared with class F fly ash.

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The eastern Nankai accretionary prism toe was surveyed to evaluate the nature and deformation of its frontal thrust. According to the determined porosities and yield strengths, turbidites were successively buried down to depths of 250–300 m before accretion, and were then exposed at the prism toe by uplift along the Tenryu frontal thrust during 3.4–1.98 Ma. Consolidation tests provided reasonable estimates of burial depth and, when combined with exposed sediment dates, yield prism toe uplift rates of 0.74–2.27 m ka–1. The displacement along the frontal thrust is estimated to be 500–900 m and the slip rates are 1.47–4.55 m ka–1, corresponding to the highest class of active faults on land in Japan. During the surveys of the Tenryu frontal thrust zone, we discovered a new active fault scarp that was several tens of centimetres high, interpreted to be a protothrust located c. 100 m south of the frontal thrust. This scarp is associated with chemosynthetic biocommunities. The thrust might potentially be the result of displacement during the East Nankai (To-Nankai) earthquake (Mw 8.1) in 1944. These lines of evidence indicate that the Tenryu frontal thrust is still active and that displacement along the thrust might induce a tsunami during future Tokai or To-Nankai earthquakes. [ABSTRACT FROM AUTHOR]

Consolidation settlement tests are costly and time-consuming, whereas tests for determining soil physical properties can be performed very rapidly and at lower costs. Therefore, it will be very helpful if the soil compression index (CC) can be determined using soil physical parameters. This study investigated correlations between the CC and the physical properties of undisturbed and remolded Tehran clay by performing 125 consolidation tests and through determining the physical properties. Based on the results, the correlations between the CC and dry density (γd), between the CC and initial void ratio (eo), and between the CC and wet density (γw) are valid and have correlation coefficient (R2) of 0.87, 0.87, and 0.89, respectively, for undisturbed Tehran clay. These correlations have been proposed for engineering applications in this area. Furthermore, available empirical correlations were compared with those presented in this study and the results suggested that the low accuracy of some of the available correlations for estimating the CC of Tehran clay soil required accurate evaluations before using them in engineering applications. Moreover, using artificial neural network showed high potential in predicting the CC and have coefficient (R) close to 1. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Shenzhen University Science & Engineering is the property of Editorial Department of Journal of Shenzhen University Science & Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Warm frozen soil will generate remarkable deformation under loading or temperature rise. In order to fully recognize the deformation properties and mechanism of warm frozen soil, a series of laboratory tests were conducted to study the consolidation deformation for frozen soil with different water contents of 40%, 80% and 120% at different temperatures (-0.3，-0.5，-0.7，-1.0 and -1.5 ℃) under stage continuous loading conditions (0.1，0.2，0.3，0.4 and 0.5 MPa). The compression parameters consisting of compressibility modulus and compressibility index and secant modulus were obtained on the basis of compression tests. The results show that the values of compressibility modulus Es1-2 are located in high compressibility region, exponential function can perfectly describe the relationship between compressibility index and temperature, ε-p curves are basically in accordance with hyperbolic model. Consolidation coefficient obtained from tests can be evaluated by adopting Taylor’s t method. The test results indicate that the consolidation coefficient of warm frozen soil has the magnitude of order just the same as that of ultra-soft soil, the relationship between consolidation coefficient and consolidation stress obeys the same regulation law as a soft soil does. In order to simulate the process of consolidation test, one-dimension Terzaghi consolidation differential equation for warm frozen soil was proposed on account of the three phase composition and mass conservation and principle of effective stress. A theoretical expression of consolidation coefficient was derived spontaneously. We compared the magnitude of consolidation coefficient between theoretical values and experimental values. Meanwhile, the change regulation between consolidation coefficient and temperature had been discussed. It is concluded that the deformation mechanism of warm frozen soil cannot be explained by Terzaghi consolidation theory. [ABSTRACT FROM AUTHOR]

Copyright of SDU Journal of Engineering Sciences & Design / Mühendislik Bilimleri ve Tasarım Dergisi is the property of Journal of Engineering Sciences & Design and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The paper aims to comparison the permeability coefficient in non-cohesive soils by the method of test pumping and based on tests in a consolidometer. The tests were carried out on 18 types of non-cohesive soils with different fraction. Pumping tests were carried out according to the standard method i.e. by making one well with a diameter of 400 mm and installing two piezometers at different distances from the well. The water table change was measured in piezometers during water pumping from the well. Tests in the consolidometer were carried out on soil samples that were fi rst compacted to the same density index as in the test site. The tests were carried out with a continuous inflow of water from below with constant gradients of 0.50. The tests presented in the paper allow to verify and compare the values of the permeability coefficient in non-cohesive soils determined in the fi eld and laboratory tests. [ABSTRACT FROM AUTHOR]

Consolidation coefficient (Cv) is one of the key parameters in calculation of soil settlement rate. This parameter can be determined using one-Dimensional consolidation test. Prediction of Cv in fine- graded soils with different Liquid Limit (LL) and Plasticity Index (PI) is also substantial to have a better understanding of soil behavior. In the present study, two fine-graded soils encompassing a broad range of liquid (LL) and plastic limits (PL) are selected and conventional consolidation tests are conducted on these samples. The samples are tested using their natural water content. It was observed that increasing liquid limit and plasticity index decreases Cv. [ABSTRACT FROM AUTHOR]

Abstract In this study, the investigation of volumetric changes in soil containing montmorillonite and kaolinite and mixtures of the two has been carried out using the discrete element method (DEM). In order to achieve this goal, seven clay samples containing montmorillonite and kaolinite were prepared using the DEM by modeling all physicochemical forces between particles during consolidation testing. Particles were simulated in both flexible and non-flexible modes. The consolidation coefficients along the loading and unloading paths were found to be dependent upon the montmorillonite content of a given mixture. The results of analysis were then compared with those from laboratory testing. [ABSTRACT FROM AUTHOR]

A thorough knowledge of the consolidation behavior of highly saturated soil under time-dependent stress is essential for the design and construction of abandoned-soil dump sites in the soft soil regions of China. In this study, one-dimensional consolidation analytical solutions are derived for such soil under one-way and two-way drainage conditions, accommodating the time-dependent stress created by various dumping protocols. Representative soil samples are obtained, and consolidation tests are conducted with various saturation degrees (one-way drainage) and loading protocols (two-way drainage), to verify the consolidation equation and determine its range of applicability to various saturation degrees. The effects of layer thickness, dumping type, and compaction degree on the consolidation behaviors of highly saturated abandoned-soil dumps are investigated. The one-dimensional consolidation equation is applicable to soil with saturation degree not lower than 75% under instantaneous stress, stepped stress, and linear stress. The pore pressure distribution with depth is not symmetrical; the eccentric distance of consolidation degree increases with increasing layer thickness in the stress application stage and is approximately zero in the stress keeping stage. The pore pressure at middle of the soil layer increases with increasing layer thickness and decreases with increasing dumping rate from the completion of soil dumping. With increasing compaction degree, the middle pore pressure increases, while the surface settlement decreases. In the premise of the stability of an abandoned-soil dump, where the goals are to reduce post-construction settlement and to shorten the consolidation process of the entire soil layer, the important factors are smaller layer thickness, higher dumping rate, and larger compaction degree. • 1D consolidation model was established for highly saturated abandoned-soil dumps. • The model was validated by conducting large-scale consolidation tests. • The model was applied to an abandoned-soil dump via sensitivity analysis. • The model is applicable for soil with S r >75% under instantaneous, stepped, linear stresses. • Smaller layer thickness, higher dumping rate, larger compaction degree benefits such dumps. [ABSTRACT FROM AUTHOR]

The Neogene Miyazaki Group comprises forearc basin sediments exposed onland in South Kyushu in Southwest Japan, and is characterized by significant spatial variations in consolidation despite the minor differences in depositional ages. The Miyazaki Group is divided into three lithofacies (the Aoshima, Miyazaki, and Tsuma facies) from south to north. To evaluate the factors controlling lithification in the basin, the physical properties of the sedimentary rocks and the calcareous nannofossil biostratigraphy were investigated. The upper parts of the Aoshima and Miyazaki facies and the lower part of the Tsuma Facies were deposited at the same time (5–6 Ma), and have minor differences in maximum paleo-temperatures (97–116, 85–99, and 80–94 °C, respectively), but major differences in porosity (15.9%, 25.5%–26.9%, and 26.1%–31.6%) and consolidation yield stress (38.2, 13.8–16.2, and 13.6–15.5 MPa). These findings indicate that the porosity reduction associated with consolidation is a more important control on the lithification than the depositional age and maximum temperature. There is a large difference in maximum burial depth between the Aoshima (>3500 m) and Miyazaki facies (<1600 m). It represents variations in sedimentary depositional environments in the Miyazaki Group: the Aoshima Facies were deposited in the deep-marine depocenter and deeply buried, whereas the Miyazaki and Tsuma facies were in the shallower marine facies and shallowly buried. After the deposition, only the southern part of the Miyazaki forearc basin was largely uplifted, making distribution of the highly consolidated sedimentary rocks there. The large amount of uplift in the Aoshima Facies was apparently due to the subduction of the Kyushu–Palau Ridge beneath the forearc basin. • Lithification is largely controlled by overburden rather than temperature and ages. • Consolidation tests for samples with small void ratio (0.1–0.2) were validated. • Major spatial variation in consolidation yield stress (p c) in the Miyazaki Group. • Minor variation in the depositional age and vitrinite reflectance (R O). • The variations represent the burial/uplifting histories reflect to regional tectonics. [ABSTRACT FROM AUTHOR]

In this paper, stress-strain-dilatancy relationships of normally consolidated Dhaka clay is presented. Two constitutive models Cam-clay model (both original and modified) and sub loading tij model are used in this paper. To obtain the parameters, drained triaxial tests of saturated cylindrical specimens under compression is conducted. One dimensional consolidation test is also conducted to obtain other model parameters namely compression index and swelling index. Total four sets of the undisturbed specimen are prepared where each set contains two specimens. Consolidated drained triaxial compression tests are conducted on first three test sets and thereby stress-dilatancy relation in compression condition is evaluated. To understand the behavior in extension one-dimensional consolidation test and drained triaxial test are performed on the test set four to obtain the model parameters. It is observed from the stress-dilatancy relationship that, sub loading tij model can well describe the stress-dilatancy behavior of normally consolidated Dhaka clay than that of the Cam-clay model both in compression and extension conditions. In compression condition, sub loading tij model presents almost a unique stress-dilatancy relationship for all three sets of specimens. Also in extension condition, a unique relationship between stress and dilatancy is observed where Cam-clay model failed to describe it uniquely. Therefore, sub loading tij model can be used with better accuracy for the Dhaka clay. [ABSTRACT FROM AUTHOR]

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To investigate the effect of structure on the compressibility of peaty soil in Kunming, Yunnan, a series of one-dimensional compression tests were carried out for disturbed and undisturbed soil samples with depth from 16.5 to 17.0 m. The test results show that by drawing method, the pre-consolidation pressure is 91~105 kPa, and the over consolidation ratio is 0.71~0.82, which illuminates that the soil is in the under consolidated state. The consolidation yield stress of disturbed soil samples is only 60~72 kPa, which shows that the peaty soil has strong structure. Due to the influence of soil structure, the compression index of undisturbed soil samples is less than that of disturbed ones when the consolidation pressure is small. With the increasing of consolidation pressure, the structure of undisturbed soil samples is destroyed, and the compression index is gradually increased and exceeds that of disturbed soil samples. With the increasing of load, the compression amount increases sharply, and the consolidation coefficients of both undisturbed and disturbed soil samples show decreasing trend. The secondary consolidation coefficient is 0.071~0.101, and the secondary compression coefficient is 2.00%~2.85%, which can be classified as a soil with high or very high secondary compressibility. [ABSTRACT FROM AUTHOR]

Artificial neural networks (ANN) as new techniques employed for the development of predictive models to estimate the needed parameters in geotechnical engineering to be used for comparison with laboratory and field tests and consequently reduce the cost, time, and effort. Flexible computing techniques are using an alternative statistical tool to analyze and evaluate experimental data from 102 consolidation tests on a variety of undisturbed soils from Ramadi city. The regression equations are developed to estimate the compression index and the compression ratio from index data. Multi-Layer Perceptron (MLP) network model is used to calculate compression index and a compression ratio of soils and comparing with the multiple linear regression statistical model MLR. It is found that the MLP showed a higher performance than MLR in predicting Cc and Cr and model accuracy between 0.81 to 16 percent. This will provide a good method for minimizing the potential inconsistency of correlations.