Study On The Disturbed Horizontal Earth Pressure And Frame Bridge-Disturbed Soil Interaction Mechanism In Mining Area

When a frame bridge is located in a mining area,the mining of the underground coal seam would disturb the surrounding soil around the frame bridge,and the earth pressure of the frame bridge would be altered,thus further leading to the internal force change of the frame bridge,resulting in the safety of the frame bridge being compromised.Consequently,it is very important for the safety of the frame bridge that the disturbed earth pressure of the frame bridge and interaction mechanism between the frame bridge and soil.In this paper,a systematic study is carried out regarding this scientific problem.The main work and research results of this paper are as follows:(1)Based on the relative displacement characteristics of the frame bridge and soil in the mining area,the horizontal earth pressure test of the translation mode and rotation mode of the wall is carried out,and the influence factors are studied.The results show that the distribution of the horizontal earth pressure is related to the types of soil,wall movement modes and wall displacement.(2)The single spring element of sand and double spring element of clay horizontal earth pressure theoretical model is established,and the theoretical formula of the horizontal earth pressure of sand and clay under different wall displacement modes is derived.The disturbed parameters of loose sand,medium dense sand and clay are fitted.The backfill is regarded as a combination of a series of spring elements and a rigid-perfectly plastic body.The rigid-perfectly plastic body is related to the disturbed cohesion and disturbed internal friction angle,disturbed external friction angle and disturbed angle of splitting.The earth pressure is studied from the perspective of soil disturbance,then compared with the model test,and the results are shown to be basically consistent.(3)The interaction mechanism between the frame bridge and disturbed soil in the mining area is studied,and the relative movement modes of the frame bridge and disturbed soil are identified.Based on the probability integral method,the relative displacement formulas of the frame bridge and disturbed soil in the compression zone and the inflection point are deduced.Combined with the spring element disturbed horizontal earth pressure,the theoretical mechanical model of the disturbed horizontal earth pressure in the compression zone and inflection point are established.(4)The finite element model of the frame bridge and disturbed soil is established.The interaction between the frame bridge and disturbed soil when the frame bridge is located at the inflection point and compression zone in the mining area,with sand and clay,is simulated The influence of the compression displacement of the soil,tilt value of soil and maximum subsidence of the basin on the horizontal earth pressure of the frame bridge are analyzed.(5)It is established that the internal force calculation method of the frame bridge under the interaction between the frame bridge and disturbed soil in the mining area,and a program is established.The feasibility of the program is verified by theoretical calculation.At the same time,when the soil consists of sand and clay,the internal forces of the frame bridge are located in the compression zone,the inflection point is calculated,and the internal forces are compared with not considering the effects of mining disturbance.