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Background The chairs used by mothers performing Kangaroo mother care (KMC) in hospitals in Indonesia are not ergonomically designed, so they can cause an awkward posture and musculoskeletal disorders. Objective The purpose of this study was to create an ergonomic sofa design that would reduce musculoskeletal disorders among mothers who perform KMC in Indonesian hospitals. Methods The research method was based on the Nigel Cross concept and involved anthropometric measurement conducted with 69 postpartum mothers from four hospitals in Indonesia as a basis for designing an ergonomic sofa. The sofa design was assessed using virtual human modeling with the Siemens Jack software for posture and lower back analysis. Result The Rapid Upper Limb Assessment (RULA) value of 2 and low back analysis (LBA) of 363 N obtained with virtual human modeling showed that a mother who performed KMC with the ergonomic sofa was in a safe position with a low risk of experiencing lower back injuries. The resulting ergonomic sofa design had adjusted to the anthropometry of mothers in Indonesia. The mother's posture with a simulation using the ergonomic sofa design is easily maintained and acceptable and can be categorized as safe to the user. Conclusion The ergonomic sofa design for KMC potentially improves posture and reduces the risk of musculoskeletal disorders. Further tests are needed, including prototype production and pilot testing, to determine its effectiveness.

Purpose This paper aims to focus on three-dimensional (3D) numerical simulation of a monitored urban underground road consisting of diaphragm walls supported by one row of temporary steel struts and a cover slab in the central area. In addition to the lateral wall displacements, the analysis focuses on the load development in the struts and the evolution of the total stresses at the soil–wall interface, and highlights the 3D effect on the behavior of the structure. Design/methodology/approach Computation by back-analysis has become an important contribution to the understanding of observed phenomena. In this context, this paper investigates a full 3D numerical back-analysis of diaphragm wall deformation using the finite difference code FLAC3D. Findings The instrumentation allows a deep understanding of the ground response and the soil-structure interaction phenomena. It also provides an opportunity to validate numerical models. Using a soil model with simple failure criteria, the wall displacements are strongly influenced by the soil deformation modulus. The strut stiffness considerably influences the wall behavior. The geometrical effects have a significant impact on the induced wall displacements. Originality/value In the present study, the main soil geotechnical characteristics were deduced from laboratory and in situ tests. However, Young’s modulus of the soil has been adjusted to take account of the unloading effect. In the same context, the non-linearity of the elastic characteristics of the steel struts has been taken into account by modeling the struts using their experimental stiffness instead of their theoretical rigidity.

In this research, three- dimension finite difference method was applied to simulate the tunnel excavation by earth pressure balance (EPB) boring machine of Tehran Metro Line 7 tunnel in Iran. Sensi...

Economic and environment-friendly design focuses on a reduction of construction material used, construction time spent and energy consumed within the buildings construction and service time. Regarding deep foundation systems and retaining structures for excavations this paper highlights the important role of enhanced geotechnical design and independent quality assurance by means of the 4-eye- principle.

Rock mechanical parameters and their uncertainties are critical to rock stability analysis, engineering design, and safe construction in rock mechanics and engineering. The back analysis is widely adopted in rock engineering to determine the mechanical parameters of the surrounding rock mass, but this does not consider the uncertainty. This problem is addressed here by the proposed approach by developing a system of Bayesian inferences for updating mechanical parameters and their statistical properties using monitored field data, then integrating the monitored data, prior knowledge of geotechnical parameters, and a mechanical model of a rock tunnel using Markov chain Monte Carlo (MCMC) simulation. The proposed approach is illustrated by a circular tunnel with an analytical solution, which was then applied to an experimental tunnel in Goupitan Hydropower Station, China. The mechanical properties and strength parameters of the surrounding rock mass were modeled as random variables. The displacement was predicted with the aid of the parameters updated by Bayesian inferences and agreed closely with monitored displacements. It indicates that Bayesian inferences combined the monitored data into the tunnel model to update its parameters dynamically. Further study indicated that the performance of Bayesian inferences is improved greatly by regularly supplementing field monitoring data. Bayesian inference is a significant and new approach for determining the mechanical parameters of the surrounding rock mass in a tunnel model and contributes to safe construction in rock engineering.

To demonstrate how public health emergency systems can use health systems tools to analyze and learn from critical incidents, we employed a facilitated look-back approach to review the public response to a chemical spill in Charleston, West Virginia. We reviewed official reports, news articles, and other documents; conducted in-person interviews with key public health and emergency response officials and local community stakeholders; and organized a facilitated look-back meeting to identify root causes of the problems that were encountered. The primary response challenges were (1) public distrust stemming from scientific uncertainty about potential harms of chemicals involved in the spill and how this uncertainty was communicated and (2) communication within the public health system, broadly defined. We found that to address inherent uncertainty, health officials should acknowledge uncertainty and tell the public what is known and unknown, and what they are doing to get more information.

This paper deals with analytical models of retaining walls interacting with soil, whose mechanical properties are influenced by penetrating moisture. Specifically, urban masonry walls are here considered. The proposed simplified procedure takes rainfalls as the intensity measure dependent on rain duration and return period. Growing levels of imbibition of the soil behind the wall determine a de-crease of the strength parameters of the soil. A geometry of the section at each step of imbibition is analyzed considering a set of soil layers with modified properties over time. The method is applied to a section of the Volterra historical urban walls named “Sperone” which was affected by a relevant collapse occurred in March 2014: a back analysis of the soil-structure section is also proposed to re-place the collapse.

In this chapter, we present an efficient Bayesian back-analysis procedure for braced excavations using wall deflection data at multiple points. A response surface method is adopted to efficiently evaluate the wall response. Deflection data for 49 wall sections from 11 case histories are collected to characterize the model error of the finite element method for evaluating the deflections at various points. A braced excavation project in Hangzhou, China is chosen to illustrate the effectiveness of the proposed procedure. The results indicate that the soil parameters could be updated more significantly for the updating that uses the deflection data at multiple points than that only uses the maximum deflection data. The predicted deflections from the updated parameters agree fairly well with the field observations. The main significance of the proposed procedure is that it improves the updating efficiency of the soil parameters without adding monitoring effort compared with the traditional method that uses the maximum deflection data.

Chau Thoi stone quarry is an old open pit mine in Binh Duong province of Vietnam, where the cut slopes are the sources of prone rockfall. Several rockfalls have occurred in this area and rockfall threatens the tourists. This case is also typical of a number of stone mines in the region. In the study, geological measurements are taken to obtain the field condition with the focus on the rock fractures. Based on the data, kinematic analysis is carried out using the DIPS software for the identification of rock slope failures. The results are then used in the analysis of rockfall. Herein, rockfall simulations are carried out by the rigid body method using the RocFall software for the analysis of bounce height, maximum runout distance, trajectories, velocity, and intensity of falling rock block. Observation at the site may be used for the back analysis. The result shows the modes of slope failures that may occur and sites that are prone to failure. The model parameters can be investigated. The vulnerable distance of rock traveling, bounce height and trajectories, velocity, and energy of rock block will be in the results. The result of this study may be useful for selection and designing protection measures and for the planning of land use hazard areas for further development. The study will be useful reference for other stone mines in the region for both exploiting work and closure of the mine.

Geotechnical parameters play key roles in constructing and developing civil engineering projects, especially underground structures. One of the conventional methods to evaluate the tunnels’ behavior and safety is applying a back-analysis method to assess the displacement amount during the construction of different parts of the tunnel. Applying this method and using displacement values obtained by tunnel monitoring, the estimated values of geotechnical parameters may converge to their real values. The present study was conducted to improve the estimation accuracy of geotechnical parameters for the tunnel route of Karaj (located 36 km west of Tehran, Iran) subway using the alternative univariate back analysis in FLAC3D software and modifying tunnel maintenance requirements, accordingly. The results showed that the use of geotechnical parameters extracted using back analysis lead to a more accurate design of the tunnel. Overall, through the applied back analysis, it is possible to reduce the shotcrete thickness of some subway stations up to 43% and obtain an optimum design.

A back analysis method based on multioutput least-squares support vector regression machine (MLSSVR) and improved differential evolution algorithm (IDE) is proposed to estimate multiple mec...

At present, with the rapid development of society, concrete has been widely used in various construction. For example, building construction, bridge construction and so on, almost all construction can not be separated from concrete. Therefore, the use of concrete is also profoundly related to the quality and safety of the building. In the process of using concrete, the temperature field of concrete has a great influence on concrete. In the process of concrete construction, cracks are likely to appear due to excessive temperature difference between inside and outside, which has a serious impact on building quality and safety. Therefore, it is particularly important to study the temperature field of concrete and effectively control its temperature. Thermodynamic parameters and boundary conditions have the greatest influence on the accuracy of concrete temperature control experimental calculation. However, obtaining these relevant parameters by means of traditional experiments requires high experimental cost, and is often inconsistent with the actual situation of concrete. Therefore, on the basis of simulated annealing algorithm, this paper makes relevant improvements. Through implementation, it can be found that the improved simulated annealing algorithm can be applied in the back analysis of concrete temperature field, and relevant Suggestions and measures can be put forward for the temperature control of concrete.

An open pit highwall up to 400 m in height is being planned at a coal mine in southeastern British Columbia, Canada. A geotechnical drilling program completed in 2016 identified that a thick (20‒40 m), weak, soil-like coal seam will be exposed along the base of the proposed highwall slope. A historical highwall failure at an adjacent open pit occurred in 2011 where successful monitoring resulted in no personnel injury or equipment damage. Following the failure, a review identified that a thick seam of sheared coal at the base of the slope might have contributed significantly to the failure; however, no back-analysis was performed. The discovery of a similar thick, friable, soil-like coal seam which will be exposed at the toe of the proposed highwall emphasised the need for a back-analysis of the historical slope failure to assist with understanding the previous failure relative to the design of the future wall. A back-analysis was then completed using limit equilibrium and finite element numerical modelling methods and included a review of monitoring, climate, and observational data. The finite element method best captured the site observations and data associated with the failure. This paper presents the key findings from the back-analysis including the results of the finite element modelling, as well as conclusions which were relevant to the design of the proposed highwall slope.

A method based on the least-squares method was proposed for the back analysis of water and earth loads using in situ monitoring data of a limited amount of structural strain values for a shallow shield tunnel buried in the soil stratum. Theoretical formulas were used to calculate the internal forces, conduct an assessment of the ultimate limit state, and determine the safety factors of compression and shear. Based upon all of the above, an assessment system was established, and its procedures were illustrated. The highlights of this assessment system are that only a few strain monitoring points are required for the back analysis of the external loads, the internal forces in every position of the segment are calculated by the uniform rigidity ring model, and the safety assessment is conducted by the proposed ultimate limit state formulas. According to the in situ monitoring project in Nanjing subway line 1, the monitoring data of internal forces were close to the back analysis data, which proves the reliability of this method.

It is crucial to determine geomaterial constitutive models to analyze the mechanical behavior of geomaterials and geotechnical engineering stability. Thus, identification of a geomaterial constitutive model is a very important aspect of back analysis. Because the real mechanical behavior of geomaterials are very complicated, it is difficult to identify a suitable geomaterial constitutive model based on traditional methods. Therefore, some computational intelligence methods have been used to solve this problem, and many related studies have been performed. In this study, previous research is reviewed according to the following four aspects: constitutive model approach via an artificial neural network, constitutive model description via an artificial neural network, constitutive model selection via an evolutionary computation, and constitutive model construction via an evolutionary computation. Moreover, the state-of-the-art research advancement of the four research aspects is summarized. The merits and demerits of these research aspects have been comprehensively analyzed and discussed. Finally, possible research directions to identify a geomaterial constitutive model based on computational intelligence are also provided.

This paper presents details on the design and construction of the first bored tunnels in Vietnam. These tunnels are part of the Ho Chi Minh City Metro Line 1 Project and consist of two bored tunnels each having a single track. The tunnels were constructed using Earth Pressure Balance Tunnel Boring Machine and were successfully completed in October 2018. The Two-Ring Beam Spring Structural Model was used to design the tunnel lining segments that had to be fabricated off-site. During construction the member forces developing in the installed segment lining were monitored and have been used for back analysis to verify the design model. Additionally, several instruments were deployed to monitor ground surface settlement and displacement, during construction. The data from these instruments was used to reconfigure the TBM driving and form part of the discussions in this paper.

Ergonomics research strives to make workers&rsquo, labor more efficient, safer, and more comfortable. Therefore, six digital humans and welding torch model were built and evaluated based on the Jack software in order to improve the ergonomics of welders&rsquo, standing postures. Three sets of standing welding actions were designed: walking, raising arm, and contracting arm. Through the Lower Back Analysis, Ovako Working Posture Analysis, Comfort Assessment, and Rapid Upper Limb Assessment, this paper evaluated the optimum range of the weight of the welding torch, the upper limb posture, and the neck posture of the welder. Firstly, the results show that Chinese welders should not use a welding torch with a weight of more than 6 kg when standing up. Secondly, for adult males in the 5th, 50th, 95th percentile of body size, the best operating distance is 321 mm, 371 mm, and 421 mm, respectively, and the best operating height is 1050 mm, 1100 mm, and 1150 mm, respectively, for females in the same percentiles, the optimal operating distance is 271 mm, 321 mm, and 371 mm, respectively, and the optimal operating height is 1000 mm, 1050 mm, and 1100 mm, respectively. Moreover, the horizontal and vertical rotation angle of the welder&rsquo, s neck should not exceed 15&deg, and 8.7&deg, The adjustment strategy not only has a positive effect on improving welders&rsquo, operational posture and preventing fatigue and injury to the welder, but it also develops research ideas for promoting safety from the perspective of ergonomics.

Results of laboratory tests on geocell-reinforced soils indicate negligible change in the internal friction angle and development of an apparent cohesion. If sufficient apparent cohesion to withstand applied loads on foundations can be determined, then a suitable kind of soil-geocell composite may be selected among pretested ones by laboratory means. In the present study, using numerical methods of lower bound limit analysis, the required apparent cohesion in the geocell layer to bear the applied load on strip foundations has been determined by back analysis. Effects of contributing factors were evaluated on the results for single and double layer reinforcements.

Two different back-analysis frameworks based on multivariate machine learning models used to determine the material dynamic parameters of concrete gravity dams are proposed. For the framework I, th...

A numerical-model-based approach was recently developed for estimating the changes in both the horizontal and vertical loading conditions induced by an approaching longwall face. In this approach, a systematic procedure is used to estimate the model’s inputs. Shearing along the bedding planes is modeled with ubiquitous joint elements and interface elements. Coal is modeled with a newly developed coal mass model. The response of the gob is calibrated with back analysis of subsidence data and the results of previously published laboratory tests on rock fragments. The model results were verified with the subsidence and stress data recently collected from a longwall mine in the eastern United States. Keywords: Longwall mining, Gateroad design, Flac3D, Horizontal angle, Gob loading, Hollow inclusion cells

The paper summarises key results of a class A prediction obtained from 2D and 3D finite element analyses performed for the Embankment Prediction Symposium 2016. In addition class C predictions are included and the changes in input parameters for the finite element model are discussed. Although different constitutive models have been employed in the class A prediction where short term displacements, i.e. after embankment construction, have been considered in addition to long term consolidation and creep settlements only long term displacements are dealt with in this paper. Thus, only results obtained with the Soft Soil Creep model implemented in the finite element code Plaxis are presented. Input parameters have been chosen based on laboratory and in situ experiments and verified by back calculation of undrained triaxial tests and CRS tests. 3D FEA have been carried out confirming that a 2D representation is sufficient for this problem.

Due to the development of joints, wedge failure has become the main failure type of rock slopes. Obtaining accurate parameters is an important prerequisite in studying slope stability. However, these are difficult to obtain due to the restrictions of field conditions. Based on a real and simple wedge, the method of stability analysis and parameter acquisition of a wedge with the nonlinear Barton-Bandis failure criterion is discussed, and then this method is extended to the conventional form of a wedge. With minimal available data, a simple field test and the reliability back analysis method are combined to propose a specific method for determining the most likely combination of nonlinear strength parameters when wedge failure occurs. This approach can provide a simple and practical method for determining the nonlinear strength parameters for engineering applications. Thus, the small frequent collapse incidences in jointed rock slopes can be effectively utilized to provide a reference for the prevention and control of large-scale failure.

The design of deep foundations in areas with significant background creep deformation is a challenge. In Sweden, mainly empirical methods have been used in the design of deep foundations. Generally, the predictions have been highly inaccurate, in particular with regards to the long-term deformations. Therefore, a stepwise approach is proposed, which stems from the concept of performance based design. It is shown that with the proposed approach, it is for the first time possible to perform representative back analyses of the long-term response of deep foundations in an environment with ongoing settlements. This is achieved with simplified 2D finite-element analyses using a commercially available creep model. Design assumptions and simplifications are defined based on careful back analysis of relevant case studies in the area that can be found in literature. Finally, the approach is validated by comparison with long-term monitoring of a 22-storey building on a floating piled raft.

Estimation of geomechanical parameters is a challenging task in geotechnical engineering. This paper aims to estimate the geotechnical parameters of soil layers in the Tehran Metro line no. 7 based on the field measurement data. In this study, the design of experiment (DOE) method is utilized for estimation of the geotechnical parameters. The geotechnical parameters such as the modulus of elasticity (E), cohesion (c), and the internal friction angle (φ) are estimated using Taguchi’s DOE method and displacement-based back analysis. The results of the DOE experiments are examined by the analysis of range (ANORA) to improve the accuracy of the optimization. Results show that Taguchi’s DOE technique offers more effective and precise estimation of the geotechnical parameters than a displacement-based back analysis approach. Finally, the optimal combination of geotechnical parameters is proposed based on results analysis of Taguchi’s DOE and back analysis method. It is shown that the combination of the obtained geotechnical parameters from Taguchi’s DOE method is closer to the field measurement data.

For its complicated depositing environment of surrounding rock mass for underground roadways, it is a very important work to back-calculate the mechanical parameters of surrounding rock mass by measurement displacements. To overcome the shortcomings of the traditional neural networks, a new neural network based on black hole algorithm has been proposed. Then, a new back analysis method based on new neural network has been studied. Using this new back analysis method, the mechanical parameters of surrounding rock mass for two deep roadways in Huainan coal mine of China have been back-calculated based on the measurement convergence displacements. Moreover, the good performance of the new back analysis method has been compared with those by back propagation network, neural networks based on genetic algorithm and immunized evolutionary programming proposed in previous studies. The results show that, using the back-calculated parameters, the computed displacements agree with the measured ones. And, considering the computing effect and efficiency comprehensively, the new back analysis method is the good method to determine the suitable mechanical parameters of surrounding rock mass for underground roadways.

In this paper, a new approach for back analysis of a geogrid reinforced soil (GRS) wall failure is presented. A new zero-thickness cohesive fracture element is utilized to simulate the slip surface behind the GRS wall. This element can simulate displacement discontinuity as well as tractions across the shear band effectively. The numerical results are compared with the measured values from the physical test as well as the obtained values from the typical finite element method. This paper demonstrates that the proposed finite element algorithm via discrete modeling of the shear band can effectively improve the quality of numerical back analysis of the soil failure which explains its necessity.

Forensic geotechnical engineering is an emerging discipline with a focus on understanding what went wrong, what could have happened and how failures can be prevented using engineering analysis principles in the case of failures of geological/geotechnical origin. In recognition of the importance of the topic, the International Society for Soil Mechanics and Geotechnical Engineering constituted a Technical Committee (TC) on forensic geotechnical engineering in 2005. During the first 4 years, it was designated as TC40 and subsequently designated as TC302 in 2009 in the reorganisation of technical committees. The committee conducted programmes and major conferences to bring out failure cases and identify the reasons as well as lessons learnt. In this briefing, steps involved in forensic analysis, such as collection of data and their characterisation, formulation of the hypothesis of failure, understanding of failure mechanisms, back analysis, consideration of testing and measurements in formulation of statements, reliability analysis and liability are discussed. The role of an expert witness is highlighted.

With the rapid development of information technology in geo-engineering, smart management of infrastructure is becoming a trend. According to digitization techniques, integrated construction and maintenance of infrastructure, this paper is aimed to build an automated dynamic monitoring analysis system of braced excavation to realize intelligent management based on Infrastructure Smart Service System (iS3). First, the improved KJHH model is established to be suitable for the specified soft soil area by considering the system stiffness \( EI /\gamma_{w} h_{avg}^{ 4} \) into Bayes back analysis. Second, based on the improved KJHH model, an automated dynamic monitoring analysis system can make visualization of excavation, use Bayesian methodology to update stratum parameters based on remote monitoring data, and make predictions of wall deflection and ground settlement. Finally, the applicability of automated dynamic monitoring analysis system was verified by the foundation project of Qiubi station of Ningbo metro line 3. It can provide a more reliable and effective way for safety analysis and risk pre-warning in the excavation engineering.

Recently it was shown that a stopwatch-measured IELT distribution can be transformed to a mathematical formula of a specific mathematical type distribution. The IELT distribution of men in the general population is a Lognormal distribution whereas that of Caucasian men with lifelong premature ejaculation (PE) is a Gumbel Max distribution. In this article, we developed the mathematical formula of the IELT distribution of two other previously published stopwatch-mediated IELT studies in the general male population of the USA and Europe, respectively, by investigating the fitness of various well-known mathematical probability density distributions into the IELT distribution of the two studies. The better the fitness the lower is the goodnes of fit (GOF). We found that the lognormal distribution most accurately fitted the IELT distribution of 1405 men in the general population of the USA, and 1026 men in the general population of Europe, with a GOF of 0.056 and 0.061, respectively. The current study also shows that the Lognormal IELT distribution of two European studies in Caucasian males are quite similar but that the Lognormal IELT distribution of men in the USA deviates compared to the two European IELT distributions. As the USA study also included 25% of non-Caucasian males it may be speculated that ethnical factors play a role in this deviation of the IELT curve. In conclusion, the Lognormal distribution of the IELT distribution in USA and European general male populations reconfirms our previous finding of a Lognormal IELT distribution in two random samples of the general male population in four European countries and USA. The Lognormal IELT distributions of the general male population highly contrasts to the Gumbel Max IELT distribution in Caucasian males with lifelong PE, as has previously been found.

In 1984 an embankment instability occured in a dike recently heightened in stages. After the instability, an extensive research program has been set up to back-analyse the settlements and the pore pressures measured during construction, focussing especially on the effects of shear stress and plastic yielding. Back-calculations have been performed using two uncoupled FEM codes in sequence : one to estimate initial stresses and the total stress increments at the undrained loading phases and another to simulate the intermittent consolidation. A simplified cap model has been introduced for undrained loading. The present paper presents the results of back-calculations using the Soft Soil and the Soft Soil with Creep models. Comparing them with those of the first back-calculations allow to overlook the progress made in soil modelling, to indicate the remaining vital input of engineers judgement and to propose some directions for further development.

Dahuaqiao Hydropower Station is the sixth cascade hydropower project on the upper stream of the Lancang River, and a number of slope instabilities were found in the reservoir area before reservoir impoundment. The reservoir impoundment and fluctuation of the reservoir water level generally reactivate these potential slope failures or trigger new ones. Therefore, how to cope with the influence of these slope failures on dam safety has always been the focus of attention. However, it is unwise to stabilize all these potentially instable slopes by remedial measures. Based on a two-parameter and four-level back analysis method proposed in this paper, reasonable measures for landslide management are suggested on the basis of the in situ monitoring results and back analysis of geomaterial strength parameters.

The back analysis method is widely used in geotechnical and geological engineering to guide construction and assure safety through feedback analysis and dynamic design. In this study, a back analysis framework was developed by combining a reduced-order model (ROM), simplicial homology global optimization (SHGO), and a numerical model. The ROM was used to approximate the response of the geotechnical structure. Moreover, SHGO was regarded as an optimization method for investigating the mechanical and strength properties of geomaterials based on the ROM using the developed framework. The developed framework was then verified and illustrated by application to a circular rock tunnel. The determined parameters of the rock mass were in excellent agreement with the actual values, and the deformation law predicted by the developed method was consistent with the analytical solution in the tunnel. These results demonstrate that the developed method is feasible for geotechnical and geological engineering. Further, the new framework was applied to a practical slope project. The results indicate that the proposed method is practical, accurate, and convenient when used to determine the geomaterials mechanical properties based on monitored information. Thus, our method is a promising tool for back analysis in practical geotechnical and geological engineering applications.

The improved genetic algorithm is combined into the foundation pit finite element method. On the basis of the measured lateral displacement data on site, the parameters of the foundation soils were obtained by the back analysis. Then the lateral deformation of the surrounding soil was analyzed on the condition of each different step under the foundation pit excavation according to the inversion parameters, and the calculation and analysis of lateral displacement of cement-soil pile with anchorage retaining structure was did. The results reveal that the calculated value is agreed with to the measured value, which indicates that the improved genetic algorithm is efficient to the related constructions.

To determine the seepage parameters of surrounding rock during excavation of tunnels, a program of groundwater seepage (SEEP) was developed. Then finite element models are established in SEEP with the consideration of seepage equations for continuous medium, and the correctness was verified by the comparison of FLAC3D. Moreover, seepage back analysis program (SBAP) was developed in C++ language by combining differential evolution algorithm (DE) and SEEP, and the measured values of water pressure and flow were used as input data, SBAP was applied to predict the horizontal and vertical hydraulic conductivities of the different stratum. The hydraulic conductivities predicted were inputted to SEEP, the computed values of water pressure and flow calculated by SEEP are in good agreement with the measured values. SBAP shows the faster convergence speed and precise feedback results. This program provides a means for engineers and researchers to determine seepage parameters in the seepage analysis of similar tunnel projects.

A major mining slope failure occurred in July 2012 on the East wall of the LAB Chrysotile mine in Canada. The major consequence of this failure was the loss of the local highway (Road 112), the main commercial link between the region and the Northeast USA. LiDAR scanning and subsequent analyses were performed and enabled quantifying the geometry and kinematics of the failure area. Using this information, this paper presents the back analysis of the July 2012 failure. The analyses are performed using deterministic and probabilistic limit equilibrium analysis and finite-element shear strength reduction analysis modelling. The impact of pit water infilling on the slope stability is investigated. The impact of the mining activity in 2011 in the lower part of the slope is also investigated through a parametric analysis.

Ore mining under the open-pit final slope will result in caving and large displacement movement of rock-masses surrounding the goaf. It is difficult for numerical methods that equate jointed rock-masses to a continuum to simulate the aforementioned mechanical behavior of rock-masses. However, the placing of joints in a calculation model according to their actual distribution characteristics will result in an excess of model blocks, which renders the calculation impossible. To solve this problem, a numerical modeling method based on an Equivalent Jointed Rock-mass Model (EJRM) is proposed in this paper. First, the rock-masses in the research area are simplified as an EJRM; then, a back analysis method, combining orthogonal design and numerical simulation with Discrete Element Method (DEM), is used to invert the mechanical parameters of the model; lastly, the DEM is utilized to analyze the movement and failure of the strata and surface induced by mining under open-pit slope. The Yanqianshan iron ore mine was treated as an example in the present study. Mining under the eastern slope of the open pit of the mine was simulated by means of the aforementioned method. The patterns of the failure and movement of the strata and slope at different mining stages were obtained. This numerical modeling method proposed can be used to simulate complex mechanical behaviors of rock-masses induced by underground mining.

Earth-fill dam safety and stability control during service period is important at the view point of economics and social security. Monitoring is very important to control dam security, to compare real action with predicted planning and to make good experience and opportunity for future planning. In this paper, water pore pressure and settlements in different parts of Sattarkhan dam during service period was studied. So at first, according to instrument data installed in the body of dam, calibration of numerical model done and by doing back analysis real properties of materials of dam defined. Then by using the calibrated model, pore water pressures and settlements of dam studied. Analysis carried out by Flac2D Finite Difference software. The constitutive model used was Mohr-Coulomb at the state of plane strain. Results showed that dam will be safe during service period at the view point of hydro-mechanical behaviour. Finally, stability of dam studied from the view of rapid depletion of the reservoir, which results showed safety conditions.

The aims of this study are to find a solution for the problems (lumping, adhesion, and clogging) encountered with fine-grained sedimentary materials, minimize the time and cost of excavation, and decrease the potential environmental effects due to soil conditioning chemicals used in the process of excavating a waste water tunnel. Therefore, this study will contribute important technical knowledge regarding design and implementation of excavation with TBM to the mining and construction industries as well as for optimization in mechanical engineering. In this research, real-time machine operational parameters recorded by EPB TBM and actual geotechnical parameters in an Istanbul-Buyukcekmece Wastewater Tunnel at seven selected tunnel sections were used as input data for the back analysis and assessment method. The method covers excavated materials with: (1) water and (2) soil conditioning chemicals. The influence of water and soil-conditioning chemicals of different proportions on torque, thrust, advance rate of the TBM, and plasticity and consistency indices of the material were investigated. Finally, integrated data were evaluated by multiple linear regression models.

Due to the complexity of multiple rocks and multiple parameters circumstance, various parameters are often reduced to only one parameter empirically to generalize geological conditions, ignoring the really influential parameters. A developed method was presented as a complement to 3D displacement inversion to obtain the relative important parameters under complex conditions with limited computational work. Furthermore, this method was applied to a high steep slope in open-pit mining to investigate field applicability of the developed system. Back analysis was conducted in the reality of the east open-pit working area of Daye Iron Mine and propositional steps were presented for parameters solving in complex circumstance. Firstly, multi-factor and single-factor sensitivity analysis were carried out to classify rock mass and mechanical parameters respectively according to the extent of their effects on deformations. Secondly, based on the results, main influence factors were selected as inversion parameters and taken into a 3D calculating model to get the displacement field and stress field, all of which would be the artificial network training samples together with inversion parameters. Thirdly, taking the real deformations as input for the trained back propagation (BP) neural network, the real material mechanical parameters could be obtained. Finally, the results of trained neural network have been confirmed by field monitoring data and provide a reference to obtain the matter parameters in complicated environment for other similar projects.