Study On Stability And Safety Evaluation Of Tunnel Slag Field

With the increaseing road construction mileage and the increasing number of tunnel projects,a large amount of waste slag is generated by tunnel excavation,and the amount of waste slag is huge and difficult to absorb,which needs to be accumulated and disposed in a centralized wany.The tunnel waste yard is thus generated.The tunnel spoil yard exists depending on the tunnel project,and is generally close to the tunnel construction.Under its own and external forces,it is prone to instability,landslides and debris flows,causing environmental pollution.Therefore,the stability and safety evaluation research of the tunnel spoil yard has the characteristics of typicality,wide application range and universal guiding significance.This paper took the BM tunnel slag field as the research background,focusing on the two aspects of slope stability and overall safety.Firstly,the characteristics and basic types of the tunnel spoil yard were analyzed in depth,and its its disaster forms,catastrophic influence factors and instability failure modes were explored,and the safety state evolution law was summarized.Then,on the basis of the BM tunnel spoil yard,considering the three working conditions of permanent,short-term and accidental,the slope model of the spoil yard was established by applying GEO-Studio geotechnical Analysis software,and the rainfall infiltration of the slope of the spoil yard was analyzed.The slope stability coefficient is calculated by the limit equilibrium analysis method(Morgenstern-Price,Bishop,Janbu,Ordinary),which is used to judge the slope grade of the DM tunnel spoil yard.Finally,an tunnel spoil yard safety evaluation index system was established including 17 factors such as seismic intensity,topography and safety management.A state-time dynamic variable weight model was established.Set pair analysis and interval triangular fuzzy number theory were introduced,and a set pair analysis-interval triangular fuzzy number(D-SPA-ITFN)coupling evaluation model based on variable weights of state factors was established.Taking the BM tunnel waste slag field as an example,the results of stability analysis and safety evaluation were as follows:(1)SEEP/W was used to construct a slope static stability model to explore the changing law of pore water pressure.The discard slag under initial seepage conditions is in an unsaturated state,and as the rainfall continues,the rainwater infiltration rate gradually increases,the affected area gradually deepens,the water content of the waste slag body gradually increases,and the pore water pressure also increases,and this trend is at the end of the rainfall.After that has been maintained.(2)Apply SLOPE/W was used to find the most dangerous slip surface of different algorithm models under three working conditions,and calculate the stability coefficient of the spoil yard.The calculation results show that the slope stability coefficient values of the two sections are 1.10 and 1.101,respectively.The static force is stable at the current altitude,and the stability of theⅠ-Ⅰ profile is greater than that of the Ⅱ-Ⅱ profile.(3)Based on the new stable analysis results,combined with the actual situation of the project,the evaluation indicators were streamlined,and the safety evaluation index system of the BM tunnel spoil yard was established.The coupling evaluation model was used to evaluate the overall safety of the spoil yard.The calculation result of the safety factor is 2.012,corresponding The level is Ⅲ,the safety level is medium,that is,the tunnel slag yard is slightly affected and needs to be repaired and rectified in time before it can be put into normal use.Based on the evaluation results,suggestions on the treatment of BM tunnel slag yard were put forward,such as the construction of steps,reinforcement of slopes,rehabilitation and strengthening of side monitoring.The stability and safety evaluation results are consistent with the theoretical analysis,which illustrates the rationality and feasibility of the model,and provides a reference for similar research on similar waste slag sites.