CHARACTERISTICS OF ROCKMASS STRUCTURES AT SLOPE OF LANCANGJIANG BRIDGE ALONG DALIRUILI RAILWAY

The complex distribution and combination characteristics of rockmass structural planes determine the engineering geology and mechanics properties and affect the failure mode of the rockmass slope. The slope at the Lancangjiang bridge along the DaliRuili railway is located in the Lancangjiang tectonic belt,where seismic intensity is high,neotectonic movement is active, the external force and active hypabyssal and hypergene rebuilding process are also active. Therefore,the rock mass structure of the both sides of Lancang river are very complex. Based on plentiful geologic investigation data of the engineered slope at the Lancangjiang bridge, a statistical analysis are undertaken to examine the structural planes with fitting test by the way of chiSquare and KolmogorovSmirnov method. The results show that：(1)three preferred structure planes are in the right bank; (2)four preferred structure planes are in the left bank; (3)the occurrence of those preferred structure planes are confirming with normal distributions,respectively. Statistic models of the engineered slopes are constructed to analyze the failure modes based on the statistic results. The failure model of the right bank engineered slope is sliding and fracturing; and the failure model of the right bank slope is the local rock blocks lossing stability．