Geotechnical modelling and subsurface analysis of complex underground structures using PLAXIS 3D

Abstract

In this study, analysis of complicated underground structure of Horemheb tomb (KV57) at Luxor, Egypt by using the software PLAXIS 3D is adopted and the deformation that occurs in the body of the underground structure after applied the failure load detected; the failure loads are obtained from the series of laboratory tests. Then, the structure is modelled by using finite element code to perform accurate three-dimensional analysis of deformation and stability in complex geotechnical engineering and rock mechanics. These underground monumental structures have been analyzed by finite element method FEM to obtain the deformation that accrued into the structure and so beneath of the surface and calculated the effective stress, shear stress and horizontal displacements. In order to modeling requires the soil parameters obtained from laboratorial tests. In the analysis elastic–plastic Mohr–Coulomb model is used as material model. It involves five parameters namely, Young’s Modulus (E) and poison’s ratio (ν) for soil elasticity, friction angle (φ) and cohesion (c) for soil plasticity. To set up the boundary condition, the standard fixities option is used. As a result a full fixity at the base and free condition at the horizontal side of geometry are generated. Numerical Engineering analysis for Horemheb tomb (KV57) in the valley of kings at the west bank of Luxor was carried out through the following four main steps: (1) Evaluation of surrounding rocks (marl limestone and marl shale) by experimental research and Roclab program to obtain the Hoek Brown and Mohr- Coulomb fit classification criterion and rock mass standards in particular the global strength and deformation coefficient. Also to specify the main characteristics of the Esna Shale using different methods such as swelling test, swelling potential, swelling pressure, in addition, discussion of the role of the expansive Esna Shale in the deterioration of archaeological buildings and sites. (2) Quantitative and qualitative estimates of the relevant factors affecting the stability of the tomb, especially overloading, fixed, geographic, and dynamic. (3) Integrated 3D geotechnical modeling of the cemetery environment for stress and displacement analysis and identification of volumetric strains and plastic points using advanced symbols and programs such as PLAXIS 3D. (4) The rapeutic and retrofit policies and techniques and the fixed monitoring and control systems needed to strengthen and stabilize the cemetery, where the rock mass classification refers to the rock mass where KV57 is excavated and it is poor rocks. The mechanical behavior of the rocks is simulated by assuming a foundational model to soften the elastic stress of the flexible plastic that captures fragile failure and the mechanisms of progressive substrate failure. In addition, rock pillar treatments and ground support strategies are discussed. This article represents the second phase of the numerical analysis of KV57 using PLAXIS 3D.