Research On Formation Mechanism And Reinforcement Of Shallow Soil Landslide In Jianshui Oil Pipeline MJ053 Based On Moisture-heat Coupling

The shallow surface soil of the crust is a strong influence area of rainfall infiltration and evaporation.Affected by conditions such as rainfall and evaporation,the dry-wet cycle of the shallow surface soil is obvious,and the dry-wet cycle has become an important factor affecting the stability of the shallow surface soil.In the Southwest Plateau,where the annual rainfall is large and the sun is abundant,there have been many shallow soil landslides induced by rainfall,which have brought greater threats to the safety of local residents? lives and property and infrastructure construction.Economic loss,so it is necessary to study the formation mechanism and prevention measures of shallow soil landslides due to rainfall and evaporation.This article is based on the investigation and prevention of the MJ053 landslide at the Baikun Refined Oil Pipeline Construction Water Station.After detailed field investigations and indoor and outdoor testing of the landslide,combined with the theory of unsaturated soil seepage and damp-heat coupling theory,the application theory Calculation and numerical simulation methods study the formation mechanism and stability analysis of shallow soil landslides under rainfall and evaporation,and propose treatment measures for oil pipelines.The main research results of this paper are as follows:1.Using the transfer coefficient method in the limit equilibrium method to carry out theoretical calculation and analysis of the landslide under natural,heavy rain and seismic conditions.The safety factor of the landslide under natural conditions is 1.059,and the whole is in a basically stable state.Under heavy rain and earthquake conditions The lower stability coefficients are 0.972 and 1.043,respectively,which are in unstable and under-stable states.The analysis shows that rainfall is the main factor affecting the stability of the landslide.2.Analysis of seepage field,stress field and stability of landslide under three consecutive days of heavy rainfall shows that the landslide is obviously affected by heavy rainfall and the stability decreases rapidly.Using the SLOPE/W?SEEP/W and SIGMA/W modules in the Geostudio software,the seepage field and stress field of landslide under extreme heavy rainfall are analyzed.It is found that the pore water pressure,shear strain and displacement of landslide soil increase rapidly in a short time under the action of heavy rainfall,and the stability decreases to unstable state,and then continues to decline slowly.3.Analyzing the damp-heat coupling effect of landslide under dry-wet cycle in one month,the results show that the landslide is greatly affected by climate change.With the help of the VADOSE/W module in the Geo-Studio software,it is found that the shallow surface of the landslide is greatly affected by climate change,and the middle and deep layers are basically unaffected.The surface layer of the landslide has obvious temperature accumulation phenomenon.4.Because the main threat object of the landslide is Sinopec refined oil pipeline passing through the landslide and diagonally intersecting with the main landslide direction.According to the field conditions,the comprehensive treatment scheme of two types of fully buried anti-slide piles and the feasibility of the scheme is verified by numerical simulation.