Fissured Loess Plane Strain Compression Test

There are many cracks and fissures types in loess according to their dimensions,mechanical characteristics and their formation reason and times. The planes of loess cracks isthe structure planes of dividing loess, the preponderance planes of eroding soil and cave, thecontrol planes of arising geological hazards and is the seeping channels and storing room ofgroundwater. The cracks and fissures can form network system and so can cause geotechnicaland engineering geological problems in engineering loess mass. Systematical research on themechanical properties of cracks and fissures in loess, deformation failure mechanism iscarried out by field investigation, laboratory tests, theory analysis and numerical simulation.The main achievements obtained in the thesis are as follows:Firstly, the cracks and fissures in loess are classified according to their dimensions,mechanical characteristics and their formation reason and times. Development feature of thecracks and fissures in loess under the action of the natural agent and their distribution rule inLoess Plateau of China are also summarized. Starting from the engineering conditions,summed up the fissured loess engineering geological characteristicsSecondly, Based on the results of the Plane strain compression tests, integral deformationmodes, failure types, failure feature and sabotage angle. deformation failure mechanicalmodes and material types of fissured loess are generalized. The comparisons of results of testsshow that the deformation and failure characters are affected by the mechanical property ofmother soil, angle of fissure in fissured loess, and confining pressure. Destruction of soilsamples by measuring the angle combined with theoretical calculated sabotage angle between50°-70°.Thirdly, with MIDAS/GTS finite element program, the numerical analysis model isestablished. The numerical simulation of different angles, different confining pressuresfissured loess under plane strain compression test respectively were carried. From the Fissureangle, confining pressure and stress and other aspects of soil deformation and failure factorsand results were analyzed. And compared with the model test results obtained, as a testsupplement, which shows the results are consistent.