应力分析机制下岩质边坡后缘张裂缝位置与深度求解方法  

A novel method for solving the location and depth of tension cracks at the rear edge of rock slopes under stress analysis mechanism

作　　者：邓东平[1] 彭一航 陈浩宇 DENG Dongping;PENG Yihang;CHEN Haoyu(College of Civil Engineering,Central South University,Changsha,Hunan 410075,China)

机构地区：[1]中南大学土木工程学院,湖南长沙400075

出　　处：《岩石力学与工程学报》2024年第8期1978-1997,共20页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(52278380);湖南省自然科学基金(2023JJ30670);湖南省交通运输厅科技项目(202008)。

摘　　要：坡后缘张裂缝对岩质边坡稳定性往往会产生至关重要的影响,而如何有效预测坡后缘张裂缝位置与深度成为可靠分析具有张裂缝岩质边坡稳定性的关键前提。为此,针对无节理或发育有4组及以上节理的岩质边坡,从坡后缘张裂缝形成机制出发,建立一种新的岩质边坡后缘张裂缝位置与深度求解方法。首先,应用非线性广义Hoek-Brown(GHB)强度准则,将节理的影响融入到岩体强度计算当中。然后,基于坡后缘张裂缝近似竖向发展的特点,将坡后缘岩体水平应力状态作为张裂缝形成与发展的关键指标,进而,提出获取岩质边坡后缘水平应力的微楔形体单元力学分析模型。最后,利用坡后缘竖向张裂缝自上而下的发展规律以及张裂缝终端应力水平与岩体抗拉强度之间的关联关系,进一步构建出坡后缘开裂位置与深度的判别式,以此实现岩质边坡后缘张裂缝位置与深度的确定。通过与数值模拟方法、室内试验结果以及工程实测数据对比分析,本文方法的合理性和有效性得到了验证。研究成果将为预测边坡后缘裂缝位置与深度提供理论基础,并为可靠开展具有坡后缘张裂缝岩质边坡的稳定性分析创造必要条件。The presence of tension cracks at the rear edge of a slope can significantly impact the stability of rock slopes.Effectively predicting the precise location and depth of these tension cracks is crucial for conducting a reliable analysis of the stability of rock slopes that exhibit such features.A novel method has been developed for rock slopes lacking joints or featuring four or more joints,aiming to determine the location and depth of tension cracks at the rear edge of rock slopes by considering the underlying formation mechanism of these cracks.First,the nonlinear generalized Hoek-Brown(GHB)strength criterion is applied to incorporate the influence of joints into the calculation of rock mass strength.Then,focusing on the vertical development characteristics of tension cracks at the rear edge of the slope,the horizontal stress state of the rock mass at this location is identified as a crucial factor influencing the formation and progression of tension cracks.Thereby,a micro-wedge unit mechanical analysis model is proposed to obtain the horizontal stresses of the rock mass at the rear edge of slope.Finally,leveraging the top-down development pattern of vertical tension cracks at the rear edge of slope and the relationship between the ultimate stress level of these cracks and the tensile strength of the rock mass,a discriminant formula is formulated to determine the location and depth of tension cracks at the rear edge of the rock slope.The rationality and validity of the present method have been confirmed through comparisons with numerical simulation methods,laboratory test results,and engineering data.These research findings will establish a theoretical foundation for predicting the location and depth of tension cracks at the rear edge of rock slopes,thereby facilitating reliable stability analysis of rock slopes with tension cracks at the rear edge.

关 键 词：边坡工程 岩质边坡 张裂缝 非线性GHB强度准则 坡后缘水平应力 张裂缝深度 起始开裂位置 

分 类 号：P64[天文地球—地质矿产勘探]