| 缓倾角塔柱状危岩压裂损伤-突变失稳预测 |
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| 引用本文： | 周福川,唐红梅,王林峰.缓倾角塔柱状危岩压裂损伤-突变失稳预测[J].岩土力学,2022,43(5):1341-1352. |
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| 作者姓名： | 周福川 唐红梅 王林峰 |
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| 作者单位： | 重庆交通大学 岩土工程研究所，重庆 400074 |
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| 基金项目： | 国家自然科学基金资助项目(No.51678097,No.5137821)~~； |
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| 摘 要： | 陡高边坡灰岩地区缓倾角塔柱状危岩常具有底部压裂诱发整体失稳破坏模式，其损伤-突变失稳机制属于山地灾害关键科学问题之一。以重庆南川区甑子岩W12#危岩崩塌为例，建立了荷载、水致弱化效应耦合下的损伤突变地质力学模型，获得了基于应变等价原理的损伤本构方程及总损伤度演化方程，并将水致弱化函数改进为软化系数的一元三次函数。将地质力学模型概化为等效弹簧模型，通过能量平衡原理建立损伤-折叠突变模型，获得了塔柱状危岩系统压裂失稳判据及临界突变位移特征值表达式。计算表明：W12#危岩压裂失稳时，该系统的控制变量为–0.003 251，小于0，表示该系统进入不稳定状态；计算理论突变位移起始值148.70 mm比实测位移第一拐点值154.34 mm偏小，相对误差约3.65%，偏于安全；理论损伤本构曲线、理论损伤演化曲线与现有文献数值模拟结果趋于一致，所构建的理论预测模型具有较好的适用性。其研究成果可用于预判塔柱状危岩压裂失稳损伤演化过程及突发失稳特征位移值，为灰岩区陡高边坡危岩崩塌监测预警和防灾减灾提供理论依据。
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| 关 键 词： | 塔柱状危岩 压裂失稳 损伤力学 能量守恒 折叠突变模型 |
| 收稿时间： | 2021-09-22 |
| 修稿时间： | 2022-01-12 |
Catastrophe prediction of compression-induced fracturing and failure for a tower-shaped unstable rock mass with gentle dip angle |
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| ZHOU Fu-chuan,TANG Hong-mei,WANG Lin-feng.Catastrophe prediction of compression-induced fracturing and failure for a tower-shaped unstable rock mass with gentle dip angle[J].Rock and Soil Mechanics,2022,43(5):1341-1352. |
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| Authors: | ZHOU Fu-chuan TANG Hong-mei WANG Lin-feng |
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| Institution: | Institute of Geotechnical Engineering, Chongqing Jiaotong University, Chongqing 400074, China |
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| Abstract: | The overall failure mode of a tower-shaped unstable rock mass associated with bottom compression-induced fracturing frequently occurs on the steep-high slope with a gentle dip angle in the karst regions, and its damage-catastrophe mechanism belongs to a key issue in the mountainous disaster discipline. Taking a collapse case of Zengziyan unstable rock mass #W12 in Nanchuan District of Chongqing, China, for example, a damage-catastrophe geomechanical model considering the load and the water-weakening effect was built. A damage constitutive equation and a total damage degree evolution equation were derived based on the strain equivalence principle, and the water-weakening function was developed into a cubic function in one unknown for the softening coefficient. Then, the geomechanical model was simplified into an equivalent spring model and the damage-fold catastrophe model was established by the energy balance theory. Finally, the failure criterion and eigenvalue expression of critical displacement mutation for the tower-shaped unstable rock mass were obtained. The results show that when the unstable rock mass #W12 fails, the control variant determining the stability of a fold catastrophe model is –0.003 251, which is less than zero, demonstrating that the system turns into an unstable state. The initial calculated value of the theoretical displacement mutation of 148.70 mm is smaller than the first inflection point of the measured value of 154.34 mm, and the relative error is about 3.65% which tends to be safer. The theoretical damage constitutive curve and evolution curve are consistent with the numerical results obtained in the literature, suggesting that the theoretical model has a good applicability. The research outcome can be applied to predicting the damage evolution process and the eigenvalue of critical displacement mutation for the compression-induced fracturing and failure of a tower-shaped unstable rock mass. It also provides a theoretical basis for monitoring and early-warning of the steep-high unstable rock mass collapse and disaster prevention and mitigation in limestone area. |
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| Keywords: | tower-shaped unstable rock mass compression-induced fracturing and failure damage mechanics energy conservation fold catastrophe model |
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