Analysis Of Deep Excavation Research Articles

Analysis of deep excavations in clay under the undrained and plane strain condition with small strain characteristics

The nonlinearity and small strain characteristics of clay are predominant factors to affect the analysis accuracy of surface settlement induced by deep excavation in soft clay. In this study, we use a newly developed constitutive model, namely the undrained soft clay model, to simulate the nonlinearity of soft clay and to describe the degradation of elastic Young's modulus with the increasing stress level, ranging from small strain to near failure. The parameters of the formula can be obtained from conventional soil tests. One well-documented case history is then used to show the parameter determination procedure and validate the proposed model. The states of strain and stress paths for the soil in the excavation are also studied to validate the rationality of the model. Besides, two additional case studies are conducted to verify the model further.

Simulation and Analysis of Deep Excavation and Loading by Using FLAC3D

A numerical calculation code FLAC3D is used to simulate excavation of a deep foundation pit of railway station nearby pile group foundations. The horizontal deformations of pile group foundations are then calculated under different operation conditions of excavation, supporting and loading. The influence of foundation excavation to adjacent building is analyzed, which can give some reference to design and construction

Analytical Hierarchy Process Applied to Risk Analysis of Deep Excavation

The application of the analytical hierarchy process (AHP) to the risk analysis of deep excavation was investigated. Firstly, the occurring probabilities of various risk factors during deep excavation were calculated. Secondly, the aftereffects of the risks were concluded by consulting the experts. Thirdly, the weight of each risk factor was obtained by AHP. Finally, the total risk of deep excavation could be evaluated by fuzzy complex evaluation. This risk analysis method was applied to evaluate the total risk of a real deep excavation, and the exemplification verified its feasibility.

Application of nonlinear optimization technique to back analyses of deep excavation

This study presents a nonlinear optimization technique (NOT) for conducting the back analyses of geotechnical engineering problems based on the field observations. Additional auxiliary techniques are incorporated to enhance the convergence and stability of the NOT. The developed NOT and additional auxiliary techniques are incorporated into a finite element code and then applied to the back analysis of excavation-induced wall deflection. A number of hypothetical excavation cases with various scenarios of stratigraphy and two quality excavation case histories are used to validate the developed NOT, in which the dominant soil parameters are treated as target parameters. Results show that the wall deflections of all hypothetical and actual excavation cases at each stage can be accurately and efficiently back-figured. The developed NOT has a potential to be an useful tool for preventing the building damage through accurately and efficiently predicting the excavation-induced deformations at subsequent stages.

Discussion and Closure: Three-Dimensional Finite Element Analysis of Deep Excavations

Discussion and Closure: Three-Dimensional Finite Element Analysis of Deep Excavations

Closure to “Three-Dimensional Finite Element Analysis of Deep Excavations” by Chang-Yu Ou, Dar-Chang Chiou, and Tzong-Shiann Wu

Closure to “Three-Dimensional Finite Element Analysis of Deep Excavations” by Chang-Yu Ou, Dar-Chang Chiou, and Tzong-Shiann Wu

Analysis of Deep Excavation with Column Type of Ground Improvement in Soft Clay

To minimize the ground settlement induced by the excavation, the column type of ground improvement has been used in many parts of the world, possibly due to the fact that this type of soil improvement is relatively easily produced and conceptually understood. However, an analysis method and design concept has not yet been established at this time. In this paper, a method for evaluating composite material properties of the treated soil mass is proposed, in which the treated soil area is replaced by a single material during analysis. This allows a three-dimensional analysis to be performed with less computer storage and computation time. Furthermore, a slight modification was made on the method, which makes plane strain analysis also applicable to the column type of soil improvement. The analysis method was supported through a model test and a case history.

Three-Dimensional Finite Element Analysis of Deep Excavations

A nonlinear, three-dimensional finite element technique for deep excavation analysis is proposed in this paper. The technique as well as the analytical procedures for modeling the excavation processes were coded into a computer program, and the accuracy of the program was assessed. In order to minimize the number of elements and nodes without sacrificing the accuracy of analysis, a series of convergence studies were performed, which makes three-dimensional analysis computationally and economically feasible. The effect of the existence of the corner on the deflection behavior of an excavation was studied in detail by analyzing a typical excavation with soft to medium clayey subsoil stratum. By performing a series of parametric studies, a tentative relationship is developed for estimating three-dimensional maximum wall deflection of an excavation based on two-dimensional finite element results. Finally, the case of an irregularly-shaped excavation with field measurements of wall deflection was studied. The results of analyses show close agreement with field measurements.

Discussion of “ Analysis of Deep Excavation in Boston ” by Andrew J. Whittle, Youssef M. A. Hashash, and Robert V. Whitman (January, 1993, Vol. 119, No. 1)

Discussion of “ <i>Analysis of Deep Excavation in Boston</i> ” by Andrew J. Whittle, Youssef M. A. Hashash, and Robert V. Whitman (January, 1993, Vol. 119, No. 1)

Closure to “ Analysis of Deep Excavation in Boston ” by Andrew J. Whittle, Youssef M. A. Hashash, and Robert V. Whitman (January, 1993, Vol. 119, No. 1)

Closure to “ <i>Analysis of Deep Excavation in Boston</i> ” by Andrew J. Whittle, Youssef M. A. Hashash, and Robert V. Whitman (January, 1993, Vol. 119, No. 1)

Finite-element analysis of deep excavation in layered sandy and clayey soil deposits : Chang-Yu Ou & Ching-Her Lai, Canadian Geotechnical Journal, 31(2), 1994, pp 204–214

Finite-element analysis of deep excavation in layered sandy and clayey soil deposits : Chang-Yu Ou & Ching-Her Lai, Canadian Geotechnical Journal, 31(2), 1994, pp 204–214

Soil parameter determination for deep excavation analysis by optimization

Abstract This paper presents an efficient method of determining soil parameters for finite element analysis of deep excavation. Due to the limitation of soil tests, field measurements are often used to calibrate in‐situ soil properties. This process is time consuming and computationally cumbersome. In this paper, nonlinear optimization techniques are applied to determine the unknown parameters of an objective function, which is defined as the sum of the square of differences between observed and predicted values. The convergence and stability of the optimization algorithm are confirmed by three well‐known mathematical functions and a hypothetical excavation case under varied ground conditions. Finally, a case study is presented to show the reliability of the proposed soil parameter determination procedure.

Finite-element analysis of deep excavation in layered sandy and clayey soil deposits

This paper presents an application of finite-element analysis to deep excavation in layered sandy and clayey soil deposits using a combination of the hyperbolic and the Modified Cam-clay models. In the analysis, the drained behavior of cohesionless soil and the undrained behavior of cohesive soil were simulated using the hyperbolic and Modified Cam-clay models, respectively. A rational procedure for determining soil parameters for each of the models was established. A simulation of the dewatering process during excavation was proposed. The analytical procedure was confirmed through an analysis of three actual excavation cases. Finally, analyses considering pore-water pressure dissipation during the actual elapsed time for each construction phase were carried out. The results indicate that the calculated displacement of a retaining wall during excavation is smaller than that given by undrained analysis. It was thought that some degree of pore-water pressure dissipation actually occurs during the intermediate excavation stages. This results in a decrease in the final deformation of the wall and ground.-surface settlement than would be predicted by undrained analysis. Key words : finite-element analysis, deep excavation, hyperbolic model, Cam-clay model.

Analysis of deep excavation in Boston : Whittle, A J; Hashash, Y M A; Whitman, R V J Geotech Engng Div ASCE V119, N1, Jan 1993, P69–90

The authors presented a very interesting and informative case history and compared results of predictions and analyses with actual measurements of movements associated with a deep excavation in Boston. Based on their findings, authors state in synopsis of paper that the results demonstrate that reliable and consistent predictions of soil deformation and groundwater flow can be achieved by advanced methods of analysis without recourse to parametric iteration... While mainbody of paper clearly discusses limitations of finite-element anaiyses, because of incomplete and/or inaccurate subsurface data and because of approximations and simplifications in modeling construction sequence, accuracy and reliability of results of such analyses could be misinterpreted from foregoing statement. This Discussion draws attention to some of most significant limitations of analyses and emphasizes need for caution and a good deal of judgment in applying results of such analyses to design.

Analysis of Deep Excavation in Boston

This paper describes the application of a finiteelement analysis for modeling the topdown construction of a sevenstory, underground parking garage at Post Office Square in Boston. The analysis inco...

Finite element analysis of deep excavation : 10F,1R. Deutsche Beit.Zur Geotechnik,N2,1974,P150–164

Finite element analysis of deep excavation : 10F,1R. Deutsche Beit.Zur Geotechnik,N2,1974,P150–164