非贯通节理岩体岩桥力学性质弱化影响研究

【作者】 刘超；

【导师】 刘远明；

【作者基本信息】 贵州大学 ， 建筑与土木工程， 2017， 硕士

【摘要】 非贯通节理岩体是岩体工程中最常见、最重要的一种地质体。非贯通节理岩体破坏通常是由节理和岩桥破坏共同组成,整体的破坏特征表现为原生节理和自节理端部扩展的岩桥破坏面所组成的复合破坏面。在外荷载作用下,岩桥靠近节理面处会产生裂纹并向岩桥内部扩展,导致力学性质弱化。岩桥力学性质的弱化,本质上是岩桥内部微元在外部荷载作用下产生破坏,在岩桥内部形成微裂隙,微裂隙逐步连通直至破坏的力学过程。本文通过直接剪切试验来测定非贯通节理岩体在剪切破坏过程不同破坏阶段的力学性质,研究非贯通节理岩体岩桥力学性质弱化规律。通过理论分析,研究了非贯通节理岩体岩桥力学性质弱化模型,分析了非贯通节理岩体岩桥渐进弱化过程中相关参数对弱化度的影响。通过对非贯通节理岩体直剪试验下外部外立面和内部剪切面破坏分析,总结出不同连通率、不同形貌节理起伏角、不同法向应力对非贯通节理岩体破坏规律。通过对外立面和剪切破坏面分析得出非贯通节理岩体四种破坏模式:张拉破坏、张拉—剪切破坏(张拉破坏为主)、剪切—张拉破坏(剪切破坏为主)、剪切破坏。同时研究了四种破坏模式对应下的非贯通节理岩体六种弱化区域模型图,其中张拉节理两种,张拉—剪切破坏(张拉破坏为主)两种,剪切—张拉破坏(剪切为主)一种,剪切破坏一种。通过对直剪试验数据分析研究了不同连通率、不同形貌起伏角、不同法向压力对非贯通节理岩体抗剪强度影响规律。通过对弱化区域岩桥芯样抗压强度试验数据分析得出非贯通节理的弱化规律。相同连通率下,起伏角越大弱化程度越高,相同形貌节理起伏角下,连通率越大弱化程度越低。更多还原

【Abstract】 The jointed rock mass is one of the most common and important geological bodies.The failure of jointed rock mass is usually composed of joints and rock bridge failure,and the failure characteristics of the joints are the composite failure surface composed of the original joints and the failure surfaces of the rock bridge.Under the action of external load,the rock bridge near the joint surface will crack and extend to the rock bridge,which leads to the weakening of the mechanical properties.The weakening of the mechanical properties of the rock bridge is essentially a mechanical process in which the micro elements in the rock bridge are destroyed under the action of external loads.In this paper,the mechanical properties of jointed rock mass in different failure stages are measured by direct shear test.Based on the theoretical analysis,the mechanical property weakening model of the rock mass bridge is studied,and the influence of the relevant parameters on the weakening degree is analyzed.Based on the rock mass shear exterior facade and interior surface shear test failure analysis,summed up the different connectivity,joints with different topography and different angle of the normal stress on the rock mass damage law.Through the external facade and shear failure surface analysis of rock mass four failure modes: tensile failure and shear failure Zhang La(tensile failure.),shear tensile failure(shear failure and shear failure).At the same time to study the rock mass of six kinds of weakening regional model figure four failure modes corresponding to the next,the tension joint two,tensile shear failure(tensile failure.)two,shear tensile failure(shear)a shear failure,a.Based on the data of the direct shear test,the shear strength of the jointed rock mass is studied by means of the analysis of the different connection rate,different shapes and the different normal pressure.Based on the analysis of the compression strength test data of the core samples in the weakened zone,the weakening law of the non penetrating joints is obtained.Under the same connectivity rate,the higher the fluctuation angle is,the higher the weakening degree is,the lower the connectivity is,the lower the weakening degree is.更多还原