| Two thirds of land area are covered by the bedding structure of sedimentary rock approximately, while China accounted for 77.3%. Due to the wide distribution, it will encounter a large number of construction projects in stratified rock mass stability problems.However, it features layered structure not only for obvious anisotropic deformation and strength characteristics, but the failure mechanism and the method of rock mass are obviously different from homogeneous rock mass. In this paper, depending on the deep foundation pit project of old city and shantytown renovation projects in nebula electronics store number 2large of Guiyang. The anisotropic characteristics of layered rock mass were analyzed by a series of laboratory consolidated rock mechanics parameter test. On the basis of analysis,improving the ubiquitous-joint model of FLAC3 D. By Standard sample numerical experiments and comparison with laboratory test results, the correctness and accuracy of improved ubiquitous-joint model are verified. Finally applying the model to the deep foundation pit engineering, the stability of four sidewall after the excavation are analyzed.The main contents as follows:(1)The elastic modulus,uniaxial compressive strength and residual strength of rock specimens mass are studied through different angle of layered rock mass specimens uniaxial and triaxial compression numerical experiments. Analyze their variation with stratified rock mass angle ? levels and deformation intensity anisotropy. Carry out Brazilian splitting method to experiment tensile strength test with two kinds of different thickness of rock specimen. Get the tensile strength of the rock. By the direct shear test of the rock and bedding plane, get the shear strength parameter of the rock and bedding plane.(2)The elastic rock mass parameters in different levels at both directions are notconsidered ubiquitous-joint model in FLAC3 D. According to the local coordinate system level elastic constitutive relation of rock mass, through the stress of coordinate transformation,establish the whole system can reflect the characteristics of the improved model of layered rock mass. In the light of mechanical behavior, deformation and failure mechanism of layered rock mass, the failure modes can be divided into rock shear failure and tensile failure;interlaminar slip failure and tension failure. Further more, set up under the various failure models of criterion and method of the stress correction.(3)The development is carried out with VC++ 6.0 programming language to generate a dynamic link library Reubiquitous.dll file called by FLAC3 D main program at any time.Compared with laboratory experiments as well as ubiquitous-joint modeling FLAC3 D, the correctness, accuracy and superiority of the new model are verified. Meanwhile, the model is applied to rock slope stability evaluation of different strata occurrence. It is concluded that the potential sliding surface and the distribution of stability coefficient changing with the orientation and angle.(4)Improved ubiquitous-joint model can be used to deep foundation pit engineering,divided into failure of between layers and destruction of rock, and three-dimensional numerical analysis model are built, which reflect the characteristics of the topography, rock mass distribution and excavation method. According to the lateral stress, displacement and the distribution characteristics of the failure after the completion of the foundation pit by excavation, analyze the side slope stability of foundation pit. Compared with the deformation and the failure zone distribution of consequent slope and tangential slope, It is concluded that orientation and the angle of the rock had control effect to the stability of the rock slope.The research content and achievements are great significant to the study of layered rock.The stability analysis of deep foundation pit engineering result provides reference for engineering design, construction, which have a great importance to engineering practical value. |
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