Excavations cover a broad range of geotechnical engineering from building construction to open pit mining and can be the basis for a wide range of analyses. Common to all issues in this category are the release of insitu stresses when the soil or rock is unloaded. In addition, the presence of water in the ground or free water on the surface can greatly change the excavation behaviour from a seepage and stability perspective.
GeoStudio establishes insitu stresses and pore-water pressure conditions so that upon removal of the ground, rebound displacements can be computed. Steady state or transient pore-water flow systems can be simulated and incorporated into dewatering and stability evaluations. Detailed stress paths can be monitored during transient changes in pore-water pressure. In an advanced analysis, a slope failure in a pit can be accounted for as a result of a sudden collapse of unstable ground. A dynamic earthquake analysis assesses potential for generation of excess pore-water pressures in the ground or plastic deformation due to stress-redistribution.
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This example is about making an excavation below the watertable. The prime objective is to look at the change in pore-pressures and the possibility of creating negative pore-pressures due to the unloading. A secondary purpose is to demonstrate and check on the use of a moving hydraulic boundary condition on the excavation face.
Halim and Wong's paper in Underground Singapore 2005 presents six case histories where deflections of the shoring walls were measured during construction. The case histories show that GeoStudio has the capabilities to model the behavior of deep shored excavations in soft ground.
SLOPE/W can be used to model the stability of rock slopes using various strength models such as the Barton and Choubey (1977) and Miller (1988) for rock joints or the anisotropic function to model rock mass with linearly anisotropic strength.
The primary objective of this example is to demonstrate how the coupled formulation in SIGMA/W can be used to simulate the excavation process and associated time-dependent pore-water pressure response and deformations (i.e. swelling).
SLOPE/W is the leading slope stability software for computing the factor of safety of earth and rock slopes. SLOPE/W can effectively analyze both simple and complex problems for a variety of slip surface shapes, pore-water pressure conditions, soil properties, analysis methods and loading conditions.
SEEP/W analyzes groundwater flow within porous materials such as soil and rock. Its formulation enables analyses ranging from simple saturated steady-state problems to sophisticated saturated/unsaturated time-dependent problems.
SIGMA/W performs stress and deformation analyses of geotechnical, civil and mining works. It can perform a simple linear elastic deformation analysis or a highly sophisticated soil-structure interaction analysis with non-linear material models and coupling to seepage analysis.
QUAKE/W enables dynamic analysis of earth structures subjected to earthquake shaking, or point dynamic forces from a blast or a sudden impact load. It determines the motion and excess pore-water pressures that arise due to shaking.
TEMP/W enables analysis of thermal changes in the ground due to environmental factors or the construction of facilities such as buildings or pipelines. TEMP/W can be applied to the geothermal analysis and design of geotechnical, civil, and mining engineering projects.