Method Of Manifold Cover Lagrangian Integral Point And Its Application

With the vigorous development of China's economy,many existing highways cannot carry the rapid growth of traffic.Compared with the construction of new expressways,the reconstruction and expansion of existing expressways can save costs and occupy land.However,the highway reconstruction and expansion project is a new topic.There is no corresponding design and construction technical specification in China at this stage.The stability after excavation of the subgrade slope affects road construction and road traffic.There are still many safety problems in the roadside slope,such as the impact of slope excavation on the safety of the operating road;obstructing traffic problems;slope safety and stability issues;safety protection of slope excavation and safety monitoring of slope excavation.In the reconstruction and expansion of highways,the slope of the road faces the danger of landslides and the above-mentioned safety problems,which poses a great threat to the lives and property of personnel.The numerical calculation method for large deformation of slope after reconstruction and expansion is still in the exploration stage.Therefore,it is of great significance to carry out research on the safety and stability of roadbed slopes.This paper studies the numerical calculation method of large deformation and large deformation evolution law of subgrade slope in view of engineering difficulties such as large deformation of strong weathered subgrade slope,based on the reconstruction and expansion project of Expressway.The main research contents and results of this paper are as follows:(1)Based on the idea of manifold coverage,a four-node rectangular cover function is constructed,and method of manifold cover Lagrangian integral point is established.This double discrete method uses Euler fixed mesh and Lagrangian material points,using the material points in motion as the integral point.The method realizes the large deformation process of simulating discontinuous damage by continuous method.This method describes the deformation behavior of macroscopic objects by the motion of Lagrangian particles between the meshes,and the mesh distortion does not occur in the calculation process.It can be operated without limitation in the solution domain.Therefore.it is very suitable for simulating large deformation problems in geotechnical engineering.(2)Based on the failure characteristics and the stress-strain constitutive relation of rock,the damage criterion of rock mesoscopic unit based on strain energy density is established.Method of manifold cover Lagrangian integration point is redeveloped by C language based on the above-mentioned damage criterion.Method of manifold cover Lagrangian integration point based on strain energy density is established.It is a large deformation numerical simulation method that simulates a discontinuous failure process using a continuous method.(3)Based on the above theoretical research and the reconstruction and expansion project of Expressway,the method of manifold cover Lagrangian integration point proposed in this paper simulates the large deformation process of strong weathered subgrade slope.It provides guidance for the construction of slope engineering and the safety protection in the later stage.