Deep Foundation Pit Excavation Research Articles

Three-Dimensional Numerical Analysis of Excavation and Support of Deep Foundation Pit

Based on a project, a numerical analysis model was established by the finite difference program and the process of the deep excavation and support was simulated by computer, the distribution of the horizontal displacement and settlement of the top of slope of the slope soil were obtained. The simulation result was consistent with the test results. It shows that the method of numerical analysis can be used to the simulation of the excavation and support of Deep Foundation Pit, and it will provide the basis for the design and construction of practice project.

Three-Dimensional Numerical Analysis of Excavation and Support of Deep Foundation Pit

Based on a project, a numerical analysis model was established by the finite difference program and the process of the deep excavation and support was simulated by computer, the distribution of the horizontal displacement and settlement of the top of slope of the slope soil were obtained. The simulation result was consistent with the test results. It shows that the method of numerical analysis can be used to the simulation of the excavation and support of Deep Foundation Pit, and it will provide the basis for the design and construction of practice project.

The Analysis of Spatial Effect of Deep Foundation Pit in Soft Soil Areas

The spatial effect is very important to the deep foundation pit excavation, but a lot of things were still unknown about it. The spatial effect of a deep foundation pit in soft soil areas was researched through an engineering project monitoring and finite element simulation. The monitoring data shows that the maximum lateral deformation of the retaining wall on the longer sides of the pit was larger than the deformation on shorter sides of the pit. And the appropriate Young's modulus of the soil is recommended for simulation of the deep foundation pit excavation in soft soil areas using Abaqus finite element software.

Filed Test Studies on Internal Force of Pile in Pile-Anchor Supporting System for Deep Foundation Pit

Through the field test on the laboratory building foundation pit engineering of Northeastern University at Qinhuangdao, the distribution and variation rule of steel stress and pile moment is researched and analyzed in the process of the deep foundation pit excavation. The result shows that foundation pit excavation and applied prestressed anchor are the main factors of pile internal force change, furthermore, the latter is more effective than the former. Meanwhile, the influence of top beam to steel stress and moment of pile head can not be ignored especially. The zero position of steel stress and pile moment are basically same, which lies under foundation pit bottom. The use of limit equilibrium method more economical than elastic subgrade method in design over foundation pit bottom, however, which is opposite under it.

The Finite Element Analysis of the Deep Foundation Pit Excavation and the Model Test

The fracture theory of soil was a new developing problem in recent year. In this paper, the basic principle of fracture mechanics and the strength theory of soil were combined, and the soil-cracking strength theory was adopted to build a constitutive relation for cracked soils. In order to use such theory and to analyze how the cracked soils effect on retaining structure, we developed an elastoplastic finite element program. Finally, the calculation results from this program were compared with the surveying measured in model testing.

Research of Controlling for Pile-Anchor Joint Supporting Structure on Deformation of Deep Foundation Pits

The excavation of deep foundation pit is very complex in the field of geotechnical engineering, how to control the deformation of deep foundation pit and protect the environment is of great significance. This paper analyzed the deformation mechanism of pile-anchor joint supporting structure in detail, established a model for deformation controlling based on the reliability theory, and then analyzed the sensitivities of prestressed, pile stiffness, spacing and soil properties to foundation deformation. Combined with an engineering example, this paper verifies the stability and effectiveness of the model for deformation controlling. This study will provide some reference to similar projects.

Research and Use of the Steel Sheet Pile Supporting Structure in the Yellow River Delta

The excavation and support problem of deep foundation pit is very interested by construction engineers with the development of the high buildings in cities and exploration utilization of the underground pace. Stability and economy are the most important problems in deep foundation pit support. This paper mainly studied on stability and economy of steel sheet pile support structure. The steel sheet pile support technique was fully introduced and analyzed here, using a combined method of theoretical guidance, calculation analysis, engineering application with finite element program simulation and market investigation.

Deformation and Internal Force Analysis of Deep Foundation Pit Excavation with Outrigger-Type Diaphragm Wall

As a new technique of excavation support structures, outrigger-type diaphragm wall has got an application in deep pit engineering, though the design of its parameters still lacks theoretical guidance. Based on a large-scale deep pit case, a 3-D finite element model is presented to simulate the behavior of outrigger-type diaphragm wall using the software ABAQUS. The soil is assumed to behave as a modified Cam-clay model. The effect of the outrigger length on deformation and internal force of the supporting structure is studied. It is found that the basal heave ,the ground settlement and the horizontal displacements of the retaining wall will increase with the increase of the outrigger length, when the bottom elevation of the supporting structure keeps unchanged. When the outrigger length goes beyond a certain length, the rate of increasing becomes larger. In the outrigger-type diaphragm wall, the vertical stress of inside and outside wall approaches the maximum in the vicinity of the variable cross-section. At the same time, the variable cross-section produces a shear stress mutation because of the abrupt change of stiffness. There exists a reasonable length of the outrigger, which could meet not only the technical requirements of the supporting structure, but also the needs of saving the cost and reducing the difficulty during the construction.

Analyses of Earth Pressure on Gridding Concrete Retaining Wall in the Excavation of Deep Foundation Pit in Soft Soil Area

This paper is mainly to study earth pressure on Gcrw used as a new kind of supporting structures in the excavation of deep foundation pits in soft soil region. On the basis of the simulation of step by step excavation by using big finite element software Abaqus/CAE and considering three-dimension elastoplastic stress state, the characteristics of different earth pressure are systematically discussed upon practical engineering. By comparing simulation results with calculated results based on calculation formula of Rankine Theory, it can be seen that the earth pressure in active zone is different from theoretic active earth pressure and earth pressure at rest while walls and soil in the gridding are regarded as a whole, which is greater than the former and somewhere similar to the latter, the earth pressure in passive zone is bigger than theoretic value of passive earth pressure, it is the tensive force from partition wall that prevent the front wall from overturning. These conclusions will be helpful for design and construction of new retaining wall.