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为研究锦屏某边坡岩体在开挖卸荷条件下的岩体宏观力学参数,对该区砂岩进行室内卸荷试验研究,结果表明:相对于加载试验,卸荷过程中岩样的强度及变形参数发生了劣化,低、高围压下岩石变形及破裂形式也有所不同。为此,在对SMR及CSMR修正的基础上,提出了考虑开挖方式、边坡形态及卸荷损伤的边坡卸荷岩体的评价体系USMR法。基于USMR法对研究区边坡开挖岩体宏观参数(变形模量Em、岩体抗压强度cm?、岩体抗拉强度tm?、岩体抗剪强度参数cm和m?)进行了动态分析,并分别考虑了不同围压3?及卸荷损伤De条件下岩体参数的劣化规律。分析表明:开挖卸荷过程中岩体宏观参数发生了不同程度的劣化,拉应力区、低应力区和高应力区岩体参数的劣化规律有所不同,拉应力区及低应力区岩体力学参数对开挖卸荷更加敏感。研究结果对边坡开挖卸荷岩体的稳定性分析与评价具有一定指导意义。
In order to study the macroscopic mechanical parameters of rock mass under the condition of excavation and unloading in Jinping slope, the unloading test of the sandstone in this area is carried out. The results show that compared with the loading test, the strength of the rock specimen during unloading And the deformation parameters have been deteriorated. The deformation and rupture patterns of rocks under low and high confining pressures are also different. Therefore, based on the SMR and CSMR correction, the USMR method for evaluating the unloading rock mass is proposed considering the excavation method, slope shape and unloading damage. Based on the USMR method, the macro parameters (deformation modulus Em, rock compressive strength cm ?, rock mass tensile strength tm ?, rock mass shear strength parameters cm and m?) Of side slope excavation in the study area were dynamically The law of rock mass parameters deterioration under different confining pressures and unloading damage is considered separately. The analysis shows that the macroscopic parameters of rock mass have been degraded to different extents in the unloading process of rock excavation. The degradation laws of the rock mass parameters in tensile stress zone, low stress zone and high stress zone are different. The tensile stress zone and low stress zone rock mass Mechanical parameters are more sensitive to excavation and unloading. The research results have certain guiding significance for the stability analysis and evaluation of unloading rock mass in slope excavation.