Study On Mechanical Parameter Of Bedded Rock Mass Slope Engineering

The reasonable confirmation of rock mass mechanical parameter is a fundamental job in rock slope mechanics and engineering. Because rock mass possesses heterogeneity, discontinuity and rheology property, there exists some problems on the choice of rock mass mechanical parameter of layer rock mass slope engineering. In this paper, the currently difficult problems on rock mass mechanical parameter are carried out, which study results are applied to the slope engineering practice.The main study work in the dissertation are focused on following several aspects:1. Based on the advantages of RMR on the slope rock mass quality evaluation, GSMR(General Slope Mass Rating) method is proposed, which is applied to the evaluation of slope rock mass mechanical parameters. Intact rock strength, orientation, interval and roughness of structural plane, groundwater condition, rock quality index, slope height, basic earthquake intensity in study zone, excavation method, shape of artificial slope, the factors of affecting the rock mass mechanical properties, are all taken into account by the GSMR system. The continuous modification quadratic function or semi-logarithmic function for intact rock strength, rock quality index or structural plane spacing are put forward, and then the error caused by the subjective judgement is decreased. So the RMR value can be replaced by the GSMR value when slope rock mass mechanical parameter is forecasted, which can reflect the slope rock mass mechanical properties, what's more, the slope stability analysis can be used the GSMR value. It shows that the GSMR method is a feasible method on the slope engineering.2. Aiming at the deficiencies of using Hoek-Brown strength criterion estimate the rock mass mechanical parameter in the practical application, the microstructure tensor is adopted to describe the parameters of the Hoek-Brown strength criterion, which can consider the anisotropism of slope rock mass. The slope excavation softening factor and anchorage strengthen factor is introduced to Hoek-Brown strength criterion, and the commutated equation of the above two factors is put forward, which investigates the effect extent of blast excavation and anchorage on the slope rock mass mechanical parameters, and at the same time rock mass mechanical parameters behind blast excavation and anchorage are computed. Case research indicates that deformation modulus, tensile strength, and cohesion take linear relation with the sine squared ofthe angle between the loading direction and structural plane, which possess the anisotropism with different extents. The anisotropism of cohesion is clear specially, however the anisotropism of internal friction angle isn't very distinct and basically a constant under the undisturbed, excavated and bolted conditions. The effect extent of excavation on mechanical parameters of different slope rock mass is varying. In a general way, the influence on the hardness rock mass is greater than that on the softness one. The excavation softening factor and deformation modulus, cohesion, internal friction angle have a linear relation, but it takes index relation with the tensile strength. The deformation modulus, tensile strength, cohesion are increased greatly by the bolt strengthen factor, nevertheless the internal friction angle is increased weakly by the bolt strengthen factor. The relation between the bolt strengthen factor and deformation modulus, cohesion, internal friction angle, tensile strength of the hardness rock is linear, and the tensile strength of the softness rock possesses index relation.3. Considering a concentrated force in the middle of the rock simple beam with round section, the strain value of some points on the rock simple beam is investigated by using the strain gauge, and the relation between the strain value and the creep compliance (rheological parameter) is deducted. Then the general format of creep compliance of the system model is derived on basis of visco-elastic constitutive model theory, and the relation between the strain value and beam deflection is de...