Stability Evaluation And Protective Analysis Of The Deep Cutting Of Beijing-xinjiang Highway

With the development of highway network construction in China,more and more deep cutting slopes are used.Due to the complicated geological conditions,large height and declivity of deep cutting slopes,instability disasters frequently occur during the construction stage and later operation stage,creating the potential for security problems.Therefore,it is of great importance to evaluate the stability of the slope accurately and find out the instability risk in time.This study takes the deep cutting slope of Zhangjiakou section in Jingxin Freeway as the research subject.According to the relevant studies home and abroad,detailed investigation reports and field investigation results,the analysis of the damage situation and formation mechanism of the cutting slope along the project are analyzed.Thus,the main factors affecting the stability of the cutting slope of Jingxin Freeway are determined.Based on the previous studies,first of all,a risk evaluation index system of the deep cutting slope is established.It adopts the penalty excitation variable weight function to determine the weights of each index and TOPSIS to set up a safety assessment model for cutting slope stability.The model is employed to give a rapid evaluation of overall stability of the cutting slope S1:K23+500～K23+780 and S2:K40+980～K41+150.The result shows that S1 is in an unstable state while S2 in a less stable state.Compared with the constant weight evaluation model,the superiority and practicability of variable weight TOPSIS evaluation model in slope stability evaluation are verified,which provides a new idea for freeway slope stability evaluation.Then,the abaqus finite element software is adopted,A two dimensional numerical model is established for the four stage excavation process of the left deep cutting mudstone slope at K23+580.Through the analysis of the output stability safety factor,slope displacement during construction and plastic strain during construction,the stability variation law and deformation danger area of cutting excavation slope are confirmed so that the optimal design slope rate is determined.At last,according to the above analytical results,reasonable protection measures and slope monitoring scheme are established for the special section of the unstable slope in this project,which can be used as the prevention and control measures for the slope instability of Jingxin Freeway deep cutting.After implementing the preventive measures proposed in this paper,the stability of the slope in the project has been effectively improved.Through the above research,it lays a theoretical basis and an important engineering treatment scheme for the construction of Jingxin Freeway,establishes an evaluation index system for the stability analysis of cutting slope,and provides a reference for other project construction and operation of slope evaluation.