Research On Engineering Geological Characteristics Of Soft Rock In Some Engineering In Xinjiang

From the perspective of sedimentary petrology, geology, etc, this paper study the soft rockformation of geological conditions and the temporal-spatial distribution characteristics of theXinjiang region. Respectively from evolution of paleogeography, paleoclimate, geologicalstructure, sedimentary facies, this paper analyze geological conditions of forming Soft rockformation, and describes the soft rock temporal and spatial distribution characteristics.In order to better research soft rock engineering characteristics, this paper took somephysical and mechanical properties test, and Large-scale Finite Element analysis software wasused to analysis foundation Soft rock deformation and stress, the conclusions are drawn asfollows:(1) Rock formations of the relying engineering is mainly the monoclinic middle-thicklayered, with part low sequence fault through. The rock is clayey silt-like structure, massivestructure, minerals are mainly composed of clastic material and clay minerals. Different degree ofweathering of argillaceous siltstone with different detritus and clay mineral content.(2) This paper took disintegrating test of water physical properties. It found that Weatheringhad a great impact on the performance of rock disintegration. Strongly weathered rock body had astrong disintegrating properties, and fast disintegrating; micro～fresh rock body disintegrationproperties was weak, and disintegration speed relatively slow. Under Indoor environmentdisintegration test, soft rock disintegration showed weaker than indoor flooding conditions. Underwet and dry cycle, soaking wet and dry cycle speed is greater than the water spray wet and drycycle speed.(3) This paper did some tests to the different degree of weathering of argillaceous siltstone,which had compressive strength test, shear strength test, the wave velocity testing test and in-situtest. It was found that the different degree of weathering of argillaceous siltstone had differentstrength, the more intense weathering its strength reduce faster. Micro～fresh rock body saturateduniaxial compressive strength of30MPa, belongs to the relatively soft rock. But because of itsspecial engineering properties, and easy weathering and disintegration, its strength will bereduced. Changes in the degree of weathering and depth, rock wave velocity difference is moreobvious. Seen from pressure-deformation curve of the whole process, under repeated applied load,the rock body plastic deformation value is greater than the elastic deformation value, this isconsistent with the general characteristics of soft rock. The rock body experienced a typicalelastic stage, plastic stage and destruction stages when shear failure.(4) This paper did numerical simulation analysis on stress and deformation of dam and itsfoundation using the finite element analysis software. Through simulation results found: Weakweathered rock has little effect on the stress and deformation of the dam and its foundation.However, seen from sensitivity analysis of dam foundation deformation parameters E0, if theupper part of the dam foundation rock body weathering aggravated, dam and will have greatdeformation. The simulation analysis preliminary draw foundation Soft rock critical deformationmodulus Ec0.