| Basement constructions of hydroelectric power sans are characterized by difficult structures,big scales and problem construction.Cross the safety of engineering build,it is very sicigant to study the cut up group of basement power sans and the authenticity of the rocks sround cut up group influence.The authenticity of the surrounding rocks is influent by factors such as ground stress,rock formation surfaces,excavation methods,cut up structure,cut up spacing,and supporting means.On text,we take as an simple a cut up group consisting of three main caves of the authenticity power plant on the right bank of the Wudongde hydroelectric power in the reaches of the Jinsha River,and due to the analysis of monitoring data,a finite method uneven land numerical simulation.Process to show a more synthesized view of the excavation of cut up.Combine the insist process with validate the validity of the numerical model.Due to the above analysis,the authenticity of the surrounding rocks and the basement caves on the right bank are studyed,and the deformation influence of the surrounding rocks and the transformation in the cut up spacing are considered.Influent on the authenticity of the surrounding rocks.This Thesis Research Treatise Research Scenario :(1)Analysis the macro special conquest of the rocks during the construction of the cut up,and analysis the law of deformation and partitioning of the rocks time and space.The results statement that the rock mass of the upper arch social status collapses,desquamation block collapses.The high sidewalls form two types of block fractures side is shown as follows.When sliding onto an empty surface,the downstream sidewalls will appear as damping damage.The caves surrounding the rock melt deformation are weathered along the structural surface.The rock transformation indicates "small dome transformation,big side wall transformation "."Strong spatial influence " "Weak time effect" "Excavation locally expands the relaxation range of surrounding rocks";The unloading relaxation depth of surrounding rocks is 2 to 2.6 m,indicating the relaxation depth on the downstream side.There is.The wall is larger than the upstream side wall and add with depth.Increases the property of increasing relaxation depth.The effect of rock structure on the transformation of surrounding rocks is greater than the influence of ground stress.The main types of rock transformation around are complex deformations such as stress relaxation of adjacent shallow cavities and deformation of structural surfaces.(2)Analyze the rock deformation factors around the cave on the right bank of Wudongde,systematically study the macroscopic deformation factors of the cave,and discuss their influential factors.As a result of the study,it was found that the rock structure surface and blasting vibration have the effect of controlling the stability of the surrounding rock.In other words,blasting vibrations,steeply sloping structural surfaces with small angles and rock formations are the main causes of deformation.Structural surfaces,such as large cracks at small angles to the cave wall,facilitate deformation of the surrounding rock.The maximum deformation rates of different parts of the same structural surface are concentrated near such structural surfaces,such as the f42 fault.,Tf40 cracks,YKT1 dissolution cracks and various weak structural regions,deformation values are significantly increased.(3)Using Rhino software and FLAC-3D finite element software,establish a 3D geological generalization model of a cave group consisting of three caves of an underground power plant on the right bank of Wudongde,stress,Displacement,simulate displacement.Changes in surrounding rocks during the construction of caves Plastic zones and their change characteristics In general,the deformation characteristics of surrounding rocks during the excavation period are reflected in the subsidence of arches at the top of the cave,the bulge of the floor,the extrusion of side walls,etc...The surrounding rocks deform towards the surface of the sky as a whole.It complies with the following rules: Unloading and repulsive deformation of surrounding rocks;maximum principal stress is expressed in two stress states: compressive stress and tensile stress.Tensile stress values are generally less than 1Mpa and have a slight effect on cave stability.The principal stress value is small and is displayed as compressive stress.Shear stress is expressed as compressive shear.The two states of stress and tensile shear stress are concentrated in the four corners of the three major caves and are generally not large in size.Plastic fracture.The types of deformation are shear fracture,tensile fracture,composite fracture,etc.affected by the adjacent cave,the effect on the structure is clear,and the plastic deformation of the surrounding rock near the main transformer tunnel is serious.The rocks around the cave are greatly affected by the construction of the adjacent cave.(4)After supporting the cave,the deformation tendency of the surrounding rocks is stable,the support system exerts a better restraining effect on the deformation and damage of the surrounding rocks and bad geological structure,and the support system is expected.Requirements to be done.(5)The effect of the limestone cave group during the construction of the Wudongde right bank limestone cave group will be examined from the two aspects of the superposition deformation of the limestone cave group and the change in the limestone cave spacing.The results show that:(1)The general deformation values of the single cavern scheme and the multi cavern scheme are 40 mm and 100 mm,respectively.The deformation value of the surrounding rock under the multi-cavern scheme is usually more than twice that of the single cavern scheme.An adjacent cave will be excavated.Deformation of rocks worsens.It can be seen that the maximum tensile stress of both schemes is tensile stress,but the maximum tensile stress of the multi-cavity scheme is 0.4Mpa greater than 0.23 Mpa of a single cave.The number of adjacent caves concentrates the tensile stress more,which has a great effect on the stability of the rocks around the caves;the minimum principal stress values of the two schemes are both concentrated at-2 to-4 Mpa,Only stress concentration changes in position;shear stress is mainly affected by the conditions of the cave itself and the geological conditions.The impact of the construction of the adjacent cave will be reduced.The plastic rupture zone is greatly affected by the excavation of the adjacent cave.Single plastic zone depth cave projects are typically up to 2 m and multi-cave projects are typically 3-4 m,with intrusion phenomena that adversely affect the rock stability of the surrounding caves.Overall,excavation of adjacent caves reduces the stability of the caves.(2)When the distances between the caves are 25 m,40,and 55 m,the deformation of the rocks around the caves is usually about 10 cm,8cm,and 6cm,respectively.As the distance between the caves increases,the deformation of the surrounding rocks decreases.The stress permeation distribution phenomenon gradually disappears.There is a clear relationship between the rupture zone and the distance between the caves,indicating that the extent of plastic rupture gradually decreases as the distance between the caves increases.A 40 m spacing plan was adopted during the construction of the actual power plant caves,taking into account comprehensive factors such as the actual topography and geological conditions of the caves,project layout and engineering economics. |
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