全风化花岗岩滑坡稳定性与降雨关系分析∗

降雨是滑坡诱发的主要因素，当前我国防灾工作理念从注重灾后救助向注重灾前预防转变、从减少灾害损失向减轻灾害风险转变，因此明晰降雨诱发机理并建立合理的预警机制，对做好地质灾害防灾减灾工作至关重要。针对降雨型全风化花岗岩滑坡稳定性问题，以青岛崂山风景区全风化花岗岩返岭滑坡为实例，进行了不同含水率原状土剪切试验与大型物理相似模型试验。揭示了边坡的降雨响应规律，探究了全风化花岗岩滑坡稳定性与降雨关系，并拟合相关量化公式。同时采用ABAQUS 建立边坡流固耦合三维数值模型，基于强度折减法验证了公式的合理性。研究结果表明：（1）降雨型全风化花岗岩滑坡的破坏模式分为浸润侵蚀→表层变形→破坏加深→整体失稳4个阶段，变形期间坡体存在“ 鼓状凸起”与“片状溜滑”现象，最终发生推移式破坏；（2）边坡对降雨入渗的响应规律在水平及竖向空间上存在差异，降雨强度越大，含水率与孔压增速越大；（3）基于试验结果推导了滑坡含水率、安全系数与降雨强度、降雨持时之间的影响关系公式，数值模拟验证误差率较小，能够较好的描述全风化花岗岩滑坡稳定性与降雨之间的定量关系。研究结果为类似强~全风化花岗岩地区滑坡的预警与防治提供参考。

Analysis of the Relationship Between Stability of Fully Weathered Granite Landslides and Rainfall

Rainfall is the primary trigger for landslides. With China''s disaster prevention efforts changingfrom post-disaster relief to pre-disaster prevention, and from disaster loss reduction to disaster riskmitigation, it is crucial to understand the triggering mechanisms for rainfall-induced disasters and establisheffective early warning systems for geological disaster prevention and mitigation. To addressthe stability issues of rainfall-induced landslides in fully weathered granites, shear tests on in-situ soils with different moisture contents and large-scale physical similarity model tests were carried out in Qingdao''sLao Mountain area as an example. The slope''s response to rainfall was revealed, the relationshipbetween the stability of fully weathered granite landslides and rainfall was explored, and relevantquantitative formulas were fitted. Additionally, ABAQUS was used to establish a three-dimensionalflow-solid coupled numerical model for the slope, validating the equations through the strength reductionmethod. The research results showed that: (1) Rainfall-induced fully weathered granite landslidesfailure progressed through four stages: infiltration and erosion → surface deformation → damage deepening overall instability. The slope exhibited the phenomena of "drum-like bulge" and "sheet-likeslipping" during the deformation period, and ended up with a translational slipping. (2) The slope''s responseto rainfall infiltration showed spatial variability, with greater rainfall intensity leading to fasterincreases in moisture content and pore pressure. (3) Based on the experimental results, formulas describingthe relationship between landslide moisture content, safety factors, and rainfall intensity andduration were derived. Numerical simulation confirmed the accuracy of these formulas with minor deviation,accurately describing the quantitative relationship between landslide stability and rainfall. Theresults of the study provide insights on early warning and prevention strategies for landslides in areaswith similar strongly to fully weathered granite.