The Research On The Cracking Property Of Expansive Soils In Wet-dry Cycling Of Natural Weather And Cracking Evolution Of Cutting Slope

Expansive soils is a kind of unsaturated soils which contain lots of swelling clay minerals, and usually make structures destroyed with its strenghth decease sharply as swelling and shrinkage due to the change of its water content in the influence of natural weather.The lose steady damage of expansive soil roadbed slope is the main problem during the construction of road in the regions of expensive soils.Including of inner factors that is the diffirence of minerals content, soils crack of roadbed slope that wet-dry cycling of natural weather causes and shallow-layer slide of slope that the seepage of the rainfalls causes both are the main reasons of the lose steady damage of expansive soils slope.Therefore it has very actual meaning that studys shrinking crack property of expansive soils roadbed slope under the influence of natural weather.So this thesis with the construction of GuangXi Nanning-Youyiguan highway is background,carried out the research of the crack property of expansive soils roadbed slope.Firstly the thesis analyse the features of Ningming expansive soils from its type of origins and distributing as well as its microscopic structure, at the same time analyse the mechanism crack of expansive soils, consider that the change of its water content in the influence of natural weather is the major influencing factor which causes expansive soils roadbed slope cracking, design and carry out the crack test of expansive soils at wet-dry cycling of natural weather which simulate the actual condition of engineering. The thesis have gotten the relation between initial water content and the crack water content of expansive soils,and discover that the change of water content and wet-dry cycling of natural weather obviously control the crack of expansive soils.On this foundation, Through GuangXi Nanning-Youyiguan highway embankment road site water testing data collation, access to natural climate under expansive soil moisture changes slope law,the effecting depth of the atmospheric of the expansive soil slope of GuangXi Nanning-Youyiguan highway,and fill the expansive soil moisture variations. Combining the actual condition of expansive soils roadbed engineering of GuangXi Nanning-Youyiguan highway, the thesis have put forward the finite element analysis method of the crack of expansive soils roadbed slope, uses the hot analysis function of ANSYS, combining the technical of life and death of unit simulate the course of shrinking crack and its crack development of expansive soils roadbed slope which be caused because of the lost of water content of expansive soils.The thesis have gotten the law of shrinking crack and its crack development of expansive soils roadbed slope in naturally dry course,calculate result coincides with the engineering reality relatively.