Evaluation and improvement on analysis of plastic zone in roadway surrounding rock under unequal compression in two directions
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摘要: 以侧压系数为1的特例为基准,将依据近似隐式法得到的围岩塑性区半径与基于成熟轴 对称平面应变理论的相应解析解进行对比,发现前者存在较大理论误差。 为改进近似隐式法的 这一不足,从已有围岩水平轴上塑性区半径的估算方法出发,以轴对称应力场塑性区公式和总线 荷载集度不变的假定为基础,推导了两向不等压巷道围岩竖向(或水平)轴上塑性区半径的近似 解;然后结合近似隐式法求解的塑性区形状,相对准确地确定了两向不等压巷道围岩的塑性区范 围。 该算法不仅消除了近似隐式法在侧压系数为1时的理论误差,还克服了原估算法导致等压 时围岩弹塑性交界线处径向应力为0的理论缺陷,是一种相对合理且准确的两向不等压巷道围 岩塑性区范围的估算方法。Abstract: Basedonthespeciallateralpressurecoefficientsof1,theradiusofsurroundingrockplastic zoneobtainedbyapproximateimplicitmethodhasalargetheoreticalerrorcontrastedwiththecorre⁃ spondinganalyticalsolution of the mature axisymmetric plane strain theory*In order to improve this shortcoming,fromtheexistingestimationmethodforsurroundingrockplasticzoneradiusonhorizontal axisandbasedontheformulasofplasticzoneunderaxisymmetricstressfieldandassumptionofthe constanttotalcollectiondegreeoflineloads,theapproximateanalyticalsolutionofthesurroundingrock plasticzoneofunequalstressfieldonvertical(orhorizontal) axiswasderived*Thencombiningwith shapeofplasticzonedeterminedbyapproximateimplicitmethod,theplasticzoneofsurroundingrock underunequalcompressionintwodirectionswasrelativelyaccuratelydetermined*Theproposedmethod notonlyeliminatesthetheoreticalerroroftheapproximateimplicitmethodforthelateralpressurecoef⁃ ficientof1,but also overcomes the theoretical defects of radial stress equal to zero in elastoplastic boundaryofsurroundingrockbyusingoriginalestimationmethodwithaxisymmetricstress*Soproposed methodcouldbeconsideredasarelativelyreasonableandaccurateestimationmethodfortheplastic
zoneinroadwaysurroundingrockunderunequalcompressionintwodirections*
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