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As part of ES 521-A, 'Effect of Maximum Particle Size, Triaxial Compression and Compaction Tests,' compaction tests were performed on a gravelly material with cohesive binder to determine the effect of large-size particles on maximum dry density and optimum water content and to obtain data for use in preparing the triaxial specimens. The effect of mold diameter and the effect of scalping both with and without replacement for oversize material were also investigated.

The purpose of this study was to analyze available data on selected cohesive deltaic plain soils and provide summaries of engineering data and correlations of engineering properties according to environments of deposition of the deltaic plain of the Mississippi River. The Mississippi River deltaic plain is that part of southeastern Louisiana that borders the Mississippi River from near Donaldsonville to Head of Passes.

The results of consolidated-undrained (termed R test in Corps of Engineers nomenclature) triaxial compression tests with pore pressure measurements performed on Vicksburg silty clay (CL) are presented and analyzed in this report. All triaxial specimens were compacted with a Harvard miniature compactor to 95 percent of standard maximum density with water contents 2 percentage points wet of standard optimum. After back-pressure saturation and consolidation under four different chamber pressures, the specimens were axially loaded at rates of strain varying from 0.001 to 1.0 percent/min. The purpose of the tests was to evaluate the effects, if any, of different rates of strain on the shear strength and deformation characteristics of this particular soil. Data presented include pore pressure observations, magnitudes of deviator stresses, Mohr's diagrams, and stress path plots. R triaxial test results indicate that this lean clay, which has a liquid limit of 34, plastic limit of 22, and plasticity index of 12, is relatively insensitive to the rates of strain used in axial loading. When other materials have been tested at different rates of strain in succeeding phases of the program, more definitive guidance on rates of strain for various fine-grained soils should be possible.

It is evident that during propagation of the blast shock wave, a moment occurs when the shock wave emits an elastic wave which in time (calculating that the speed of the elastic wave is constant, whereas the speed of the shock wave decreases with time) increasingly surpasses the shock wave. The ground model and equation which describe ground behavior during blast wave action upon are studied. In initial postulates, all ground parameters are accepted as zero. The given parameters are determined from the system of equations which describes the ground state at the front of the shock wave and products of detonation at the rarefaction wave., Edited trans. of Akademiya Nauk URSR, Kiev. Dopovidi. Seriya A: Fiziko-Tekhnichni ta Matematichni Nauki, n5 p460-465 1972.

Contents: The procedure for penetration soil tests; The procedure for testing the surface layers of soil by sounding; The procedure for testing cohesive soils using vane shear and combined soil tests; The procedure for establishing a correlation between the physico-mechanical properties of cohesive soils; Investigations of the physicomechanical properties and indicative criteria of soils by the methods of penetration and sounding; The principles of the technology of soil testing by the methods of penetration, sounding and vane shear., Edited machine trans. of mono. Penetratsionnye Ispytaniya Gruntov, Moscow, 1968 p1-182, by Ray E. Zarza.

The results of consolidated-undrained (R) triaxial compression tests with pore pressure measurements performed to determine the effects of strain rate on the strength and deformation characteristics of Vicksburg buckshot clay (CH) are presented and analyzed in this report. The 1.4-in.-dia triaxial specimens were compacted with a Harvard miniature compactor to 95 percent of maximum dry density derived from the standard effort compaction test with water contents 2 percentage points wet of standard optimum. Standard caps and bases (having the same diameter as the test specimen, with 1-in.-diam rigid porous inserts and drainage connections) were used in the triaxial tests. After back-pressure saturation and consolidation under effective confining pressures of 0.5 and 5.0 kg per sq cm, specimens with an without filter strips were axially loaded at rates of strain varying from 1.2 to 0.0012 percent per minute. Data presented include stress-strain curves, pore pressure observations, final water content distributions within the specimens, and shear strength envelopes based on total stresses. (Author)

The methods suggested for predicting the variation in compressibility and relative settlement factors of loess soils are based on the correlation between indexes of the cohesive soils' physical and mechanical properties and essentially represent a further development and generalization of the two-curve method. The most typical samples of loess soils are subjected to compression under conditions of natural moistness and at varying extent of water saturation. In distinction from the method of two curves, the coincidence of the initial values of the soil skeleton's volumetric weight is not mandatory in the given instance. The authors recommend the suggested method for generalizing and analyzing the compressibility and settlement tendency of cohesive soils (including the loess-type ones) for extensive production practice., Draft trans. of Osnovaniya, Fundamenty i Mekhanika Gruntov (USSR) v4 p75-81 1971.

The book presents theoretical and practical problems of stabilizing normally moist or waterlogged soils with binders: liquid shale and furfural tars, liquid spent sulfite liquor concentrates, phosphoric acid and its salts, quicklime, calcined magnesium, cement, and mineral wastes of industrial enterprises. The properties of these organic and inorganic chemical products used in airfield and road construction are examined. Physicomechanical properties of soils stabilized with chemical products are described. Methods of chemical stabilization of soils in airfields and roads chiefly in the northwestern and western oblasts of the podzolic zone of the European part of the USSR are presented: a number of methods can be also employed in other zones. The methods presented here have been selected on the basis that their practical realization will satisfy the conditions under which the principal material for soil stabilization will be predominantly local material employed generally without heating, and suitable for application to soil, and thereby affording utilization in operation of relatively simple technological procedures. (Authro)

The report is the third in a series and concludes a study intended to establish scaling relations of forces and displacements for families of circular footings (plates and cylinders). The report contains the basic data and an analysis of the penetration results obtained from tests with circular plates and smooth-walled and rough-walled cylinders in a fat clay prepared at two strength levels. The footings ranged from 2.5 to 61 cm in diameter. In general, it was found that a dimensionless equation of the form P/c = f(z/d), where P is pressure, c is soil cohesion, z is depth of penetration, and d is diameter of the footing, appears to be adequate for scaling forces and displacements. However, the data suggest that, in weak soils, there may be a minimum footing diameter below which the scaling law does not apply. A single dimensionless plot of the data obtained for the several sizes of footings is not supported by existing bearing capacity equations. The measured curves of penetration resistance (on the base of the footings) versus depth of penetration are in better agreement with those computed by the Meyerhof equation than with those computed from Brinch Hansen's equations. (Author), See also Rept. no. 2, AD-715 980.

The results of two different methods for determining the rigidity modulus of a soft sediment are compared. In one method the resonant characteristics of a torsionally oscillating rod which are sensitive to the shear acoustic impedance of the sediment in which the rod is imbedded determine the complex rigidity. The second method utilizes the observation of the phase velocity of an interface wave at the water-sediment boundary. Shear wave speeds computed from the experimental data from both methods are quite similar in magnitude. For the sediment used here, the average value of shear wave speed determined from the interface wave experiment was 33 m/sec while the shear wave speed determined from the measured rigidity was 29 m/sec. The difference lies withing experimental uncertainty. Trends in the mass-physical properties of the sediments are investigated by comparing graphically the dependence of both the real and imaginary parts of the complex rigidity on density, porosity, sound speed, silt and clay percentages, Poisson's ratio and density times sound speed squared. (Author)

The concepts associated with the field of soil mechanics are now being applied to marine sediments. Because of the more complex nature of the mixture of fine mineral particles and sea water, some of these concepts do not always appear overly applicable. This is particularly true with regard to the deep sea clays. In view of their often very high water contents, a liquid behavior might well be assumed for many marine clays. The analytical methods of fluid mechanics do not satisfactorily explain the low strengths that are found in these soils. Thin-walled test cylinders were devised to allow testing of cohesive soils at high water contents. Over 50 tests were made of a test sediment, the majority above the liquid limit, to study the relationship of plasticity to water content. The results show that the gradation from liquid to plastic behavior encompasses a much wider range of water contents than previously considered. (Author)

Práce se zaměřuje na popis různých domácích a zahraničních metod, které lze aplikovat na výpočet únosnosti mikropilot v soudržných a nesoudržných zeminách. Hlavním bodem bakalářské práce je stanovení únosnosti mikropiloty na dvou konkrétních případech, přičemž v prvním případě se jedná o soudržnou a ve druhém případě o nesoudržnou zeminu. Následně je provedeno porovnání a zhodnocení použitých výpočetních metod s výsledky zatěžovacích zkoušek., The work focuses on the description of various domestic and foreign methods that can be applied to calculate the load-bearing capacity of micropiles in cohesive and cohesionless soils. The main goal of this work is to determine the values of the load-bearing capacity of micropiles on two specific cases, while in the first case it is a cohesive and in the second case a cohesionless soils. Subsequently, the comparison and evaluation of the used methods of calculation with the results of load tests.

Práce se zaměřuje na popis různých domácích a zahraničních metod, které lze aplikovat na výpočet únosnosti mikropilot v soudržných a nesoudržných zeminách. Hlavním bodem bakalářské práce je stanovení únosnosti mikropiloty na dvou konkrétních případech, přičemž v prvním případě se jedná o soudržnou a ve druhém případě o nesoudržnou zeminu. Následně je provedeno porovnání a zhodnocení použitých výpočetních metod s výsledky zatěžovacích zkoušek., The work focuses on the description of various domestic and foreign methods that can be applied to calculate the load-bearing capacity of micropiles in cohesive and cohesionless soils. The main goal of this work is to determine the values of the load-bearing capacity of micropiles on two specific cases, while in the first case it is a cohesive and in the second case a cohesionless soils. Subsequently, the comparison and evaluation of the used methods of calculation with the results of load tests.

Práce se zaměřuje na popis různých domácích a zahraničních metod, které lze aplikovat na výpočet únosnosti mikropilot v soudržných a nesoudržných zeminách. Hlavním bodem bakalářské práce je stanovení únosnosti mikropiloty na dvou konkrétních případech, přičemž v prvním případě se jedná o soudržnou a ve druhém případě o nesoudržnou zeminu. Následně je provedeno porovnání a zhodnocení použitých výpočetních metod s výsledky zatěžovacích zkoušek., The work focuses on the description of various domestic and foreign methods that can be applied to calculate the load-bearing capacity of micropiles in cohesive and cohesionless soils. The main goal of this work is to determine the values of the load-bearing capacity of micropiles on two specific cases, while in the first case it is a cohesive and in the second case a cohesionless soils. Subsequently, the comparison and evaluation of the used methods of calculation with the results of load tests.

Práce se zaměřuje na popis různých domácích a zahraničních metod, které lze aplikovat na výpočet únosnosti mikropilot v soudržných a nesoudržných zeminách. Hlavním bodem bakalářské práce je stanovení únosnosti mikropiloty na dvou konkrétních případech, přičemž v prvním případě se jedná o soudržnou a ve druhém případě o nesoudržnou zeminu. Následně je provedeno porovnání a zhodnocení použitých výpočetních metod s výsledky zatěžovacích zkoušek., The work focuses on the description of various domestic and foreign methods that can be applied to calculate the load-bearing capacity of micropiles in cohesive and cohesionless soils. The main goal of this work is to determine the values of the load-bearing capacity of micropiles on two specific cases, while in the first case it is a cohesive and in the second case a cohesionless soils. Subsequently, the comparison and evaluation of the used methods of calculation with the results of load tests.

Práce se zaměřuje na popis různých domácích a zahraničních metod, které lze aplikovat na výpočet únosnosti mikropilot v soudržných a nesoudržných zeminách. Hlavním bodem bakalářské práce je stanovení únosnosti mikropiloty na dvou konkrétních případech, přičemž v prvním případě se jedná o soudržnou a ve druhém případě o nesoudržnou zeminu. Následně je provedeno porovnání a zhodnocení použitých výpočetních metod s výsledky zatěžovacích zkoušek., The work focuses on the description of various domestic and foreign methods that can be applied to calculate the load-bearing capacity of micropiles in cohesive and cohesionless soils. The main goal of this work is to determine the values of the load-bearing capacity of micropiles on two specific cases, while in the first case it is a cohesive and in the second case a cohesionless soils. Subsequently, the comparison and evaluation of the used methods of calculation with the results of load tests.

The primary objectives of this research include: performing static and dynamic load tests on, newly instrumented test piles to better understand the set-up mechanism for individual soil, layers, verifying or recalibrating previously developed empirical set-up models for piles driven, in soft cohesive soils (prior LTRC Project 11-2GT), and developing an analytical methodology to, estimate the duration of pile set-up., Minor objectives include: developing a model to predict spatial distribution of excess pore water, pressure due to pile driving, establishing a relationship between vertical shaft displacement, and associated shear resistance by analyzing strain gage data from instrumented test piles, developing a method to predict the pile tip resistance at different axial tip displacements, and, calculating the total and effective stress parameters (e.g., adhesion factor).

Scour of bridge foundations is the most common cause of bridge failures. The overall goal of this project was to evaluate the applicability of the existing Hydraulic Engineering Circular (HEC-18) documents method to Louisiana bridges that are mostly situated on cohesive soils and hence develop a more reliable design method for scour depth and scour rate prediction., The errors of scour depth prediction of the HEC-18 method are mainly from three sources: (1) the driving force of scour, i.e., the hydrologic and hydraulic properties of flood flow causing scour development; (2) the resistive force of scour, i.e., the geotechnical properties of streambed soils or sediments that are removed by stream flow; and (3) the geometry, size, and shape of the obstacles (e.g., piers and pile caps). The third error source is not a focus of this study. Due to the availability of the geotechnical data on streambed soils, the second error source was investigated at a secondary priority, and the primary priority of this study was to evaluate the existing method’s applicability to cohesive soils in Louisiana using real hydrological data derived from archived satellite remote sensing data., A total of seven bridges situated on clays, silts, and sands were selected as case studies for scour analysis over a 10- to 15-year period. The hydraulic properties were determined by analyzing satellite sensing data, which were then used as inputs to the HEC-18 method via a software program WASPRO. The recorded scour survey data were also analyzed and compared with data predicted by the HEC-18 using the real flood data. Significant discrepancy existed among the HEC-18 prediction and surveyed scour depth, and the predicted values were always greater than the surveyed depth. Therefore, for cohesive soils, the HEC-18 method usually provides a more conservative design. Although the bridges were safe for the final scour depth, the method typically yields a more costly design.

Scour of bridge foundations is the most common cause of bridge failures. The Federal Highway Administration, (FHWA) has developed a design method, HEC-18, for the state Departments of Transportation (DOTs) to evaluate, the scour potential of existing bridges and predict the scour depths for new bridges. The scour models in the HEC-18, were based on a number of empirical equations that were developed primarily from laboratory fl ume studies with, limited fi eld data verifi cation. Because of the complex nature of scour process, these scour-prediction equations, recommended in HEC-18 may tend to provide conservative scour depth estimates to ensure that an adequate, factor of safety is considered for bridge scour design. Underestimation of scour depths may result in costly bridge, repairs or even catastrophic bridge failures, while overestimation may cause costly, unnecessarily deep foundations., The scour potential evaluation for existing bridges is also important. Overestimation of scour depths causes more, bridges to be misclassifi ed as “scour critical,” thus resulting in unnecessary installation of scour countermeasures, or bridge replacements. Currently, the Louisiana Department of Transportation and Development (DOTD) uses, the HEC-18 method for bridge scour design. Costs associated with the current design methods that usually lead to, conservative estimation of scour depths can be very high. On the other hand, DOTD has developed and maintained, a large database for a large number of bridge structures that are prone to scour. Those bridges were monitored and, hydrologic and hydraulic data collected. In addition, diff erent bed materials scour at diff erent rates and, because of, this fact, HEC-18 does not always accurately predict the scour depth at a certain time. A more reliable scour prediction, method is needed, especially for the clay and silty clay soils common in Louisiana, with distinct local climatic characteristics (e.g., heavy downpours, severe storms, and, hurricanes).

State Project No. 736-99-0658, This report presents the construction and performance evaluation of the LTRC reinforced-soil test wall. The 20 ft. high, 160 ft. long wall was constructed using low quality backfill. Its vertical front facing was constructed with modular blocks. It consisted of three sections reinforced with various geogrid reinforcement types and spacing. The backside of the wall was a one-to-one slope reinforced with woven and non-woven geotextiles., The test wall was constructed to evaluate the design procedure and performance of geosynthetic-reinforced structures constructed with marginal silty-clay backfill over soft clay foundation. The instrumentation program consisted of monitoring wall deformation, foundation settlement, strains in the reinforcement, vertical and horizontal stresses in the soil, and pore water pressure under the wall. Results of the monitoring program from construction through four months after completion of the wall are detailed in this report., The results of the instrumentation program showed relatively high deformations due to both the design of the wall with low factors of safety and to the high settlement of the foundation soil. These deformations, however, occurred mostly during construction. The results of strain measurements in the reinforcement were used to evaluate the effect of reinforcement stiffness and spacing on the shape of the failure surface and on the distribution and magnitude of stresses in reinforcement layers., The results show promising performance of silty-clay soils as a backfill material in reinforced-soil walls providing proper design and control of soil compaction and moisture. However, long-term performance of the wall needs to be monitored for a complete evaluation of these types of walls.

State Project No. 736-99-0658, The considerable increase of using geosynthetics in mechanically stabilized earth (MSE) walls has raised the need to evaluate their interface shear strength and pullout properties in various types of backfills. This report investigates the use of a marginal silty-clay soil of medium plasticity as a suitable backfill in MSE walls. The interface parameters between the geosynthetics and the soil were evaluated in pullout tests. The testing program included performing laboratory and field pullout tests on four types of geogrids and three types of geotextiles. Laboratory pullout tests were carried out using the large pullout testing equipment at the Louisiana Transportation Research Center (LTRC). Field pullout tests were performed in a test section of the LTRC full-scale reinforced test wall. The pullout test section contained geogrid and geotextile specimens at various wall elevations., The testing program evaluated the effect of reinforcement type, length, and confining pressure on the pullout resistance. Laboratory and field tests were performed using the same type of soil at a similar density and moisture content. Laboratory and field results compared well for the extensible reinforcements of medium to low stiffness modulus. However, field pullout results were significantly higher than laboratory results for the rigid geogrids., The pullout resistance factor (F* ) and the scale effect correction factor (a) were established for the geogrid and geotextile specimens. These values can be used to determine the pullout resistance of these types of geosynthetics at various confining pressures and specimen lengths.

00-3GT, The piezocone penetration test (PCPT) has gained wide popularity and acknowledgement as a preferred in-situ device for subsurface investigation and soil characterization. The PCPT measurements can be utilized for soil identification and the evaluation of different soil parameters. Different interpretation methods have been proposed to evaluate the strength and consolidation parameters of cohesive soils utilizing the piezocone penetration and dissipation test data. This report presents the evaluation of the capability of the current PCPT interpretation methods to reasonably predict the consolidation parameters needed to predict the total and time rate of settlement of cohesive soils. Seven sites in Louisiana were selected for this study. In each site, in-situ PCPT tests were performed and soundings of cone tip resistance (qc), sleeve friction (fs) and pore pressures (u1 and u2) were recorded. Dissipation tests were also conducted at different penetration depths. High quality shelby tube samples were collected close to the PCPT tests and used to carry out a comprehensive laboratory testing program including unconfined compression test, triaxial test and one-dimensional oedometer consolidation test. The tangent constrained modulus (M), overconsolidation ratio (OCR) and the vertical coefficient of consolidation (cv), predicted using the different interpretation methods, were compared with the reference values determined from the laboratory consolidation tests. Results of this study showed that the consolidation parameters of soils can be reasonably predicted from the piezocone penetration and dissipation test data, and hence provide a continuous profile of these parameters with depth. The results of this study were verified by comparing the predicted settlements from PCPT methods with the laboratory calculated and field measured settlements in three selected sites.