A Study On Safety Evaluation Of Building High Rock Cutting Slope

With city construction and land development, number of building rock slopes which near the buildings increased in mountainous cities. Numerous building high rock slopes are formed as the slopes are becoming more cliffy and higher. At the same time, lots of construction accidents occurred. Because of the close relation of building rock slopes to environment and human activity, its safety decides directly the safety ,economy and use of the main building , effects city construction and peoples' lives and property also. So it's essential to do research on safety evaluation of building high rock cutting slope, look for the main reason and approach of construction accident occurs, take corresponding control measures to local conditions, prevent or reduce the damage caused by building rock slope collapse.Fault tree analysis method (FTA) is a safety evaluation method applied to analyze reasons of accident and approach of accident occurs. The thesis is based on building high rock cutting slope project, uses FTA method to do research on building high rock cutting slope supported by anchor rod. Some meaning research results are made and used in actual constructions. Main research work is as follows:(1) Based on summary of shoring mode of building high rock cutting slope, analyses on type, characteristic and destruction mode of anchor rod retaining wall are made, actual construction methods in building high rock cutting slope are discussed. Induction of reasons for building high rock cutting slope accident is gave by collecting and analyzing large numbers of construction accident data.(2) System analysis of basic theory and basic method of FTA is made in this thesis. Because probability of bottom event in fault tree needs to be calculated accurately in traditional method, but it's difficult in actual project. So conception of fuzzy number is introduced to expound the fault tree analysis method.(3) Combining research on building rock slope and basing on fault tree analysis method, this thesis deeply analyzes the danger sources and danger characteristic of building high cutting rock slope supported by anchor rod retaining wall, establishes FT model of building high rock cutting slope supported by anchor rod retaining wall and makes FTA qualitative analysis of the model, searches the danger approach of building high rock cutting slope supported by anchor rod retaining wall.(4) According to research on a building high rock cutting slope construction accident occurred in Sihai Road, Chongqing, using statistical analysis, combining actual construction environment, hydrogeology, excavation support and so on, triangular Fuzzy probability value of bottom event of the construction is estimated. The probability value is substituted to the FTA model to quantitatively calculate the occurrence probability of top event and the major reason of the accident by FTA method. Based on comparison of FTA result, calculation result of construction mechanics and investigation of actual accident, the correctness of anchor rod retaining wall structure system FT model in this thesis and the feasibility of FTA safety evaluation applied to building high rock cutting slope are validated.