Study On The Ultimate Bearing Capacity Of The Upper Plate Of Karst Cave

Study on the ultimate bearing capacity of upper plate of Karst cave is very important for engineering construction in Karst areas. The methods to determine ultimate bearing capacity and the main influence factors on ultimate bearing capacity are studied based on the engineering of West Two-Ring Expressway in Guangzhou and Zhucheng Road in Hunan province. The main original work and results are as follows:Based on the field investigation and gathering of the engineering geology data of West Two-ring Expressway in Guangzhou and Zhucheng Road in Hunan province, the actual form and distribution of Karst caves are analyzed, the general geological model of Karst cave is established, the wall rock of Karst cave is classified according to Chinese Standard, and the corresponding rock mechanical parameters are obtained. By studying the mechanical property of carbonate rock, it is found that carbonate rock shows elastic-plastic properties.By comparing various methods to define ultimate bearing capacity in and out of China, semi-logarithm method which has good reliability is selected to combine with FLAC-3D numerical simulation method to determine ultimate bearing capacity in present paper. The ultimate bearing capacity of upper plate of Karst cave in various engineering conditions are presented by analyzing the characteristic of rock stress and deformation and the whole evolvement process of plastic zones in upper plate.The influence of the thickness of upper plate, the width of Karst cave, the mechanical properties of rock mass, the shape of Kast cave, joint obliquity and joint mechanical parameters on the ultimate bearing capacity of upper plate of Karst cave in various projects are studied in this paper. The joint influence curved surface of the ultimate bearing capacity by the thickness of upper plate and the width of Karst cave are drawn and some disciplinary results are achieved.By analyzing the results of ultimate bearing capacity in various projects, a predicative neural network model is established and the ultimate bearing capacity in different...