超高路堑边坡治理工程案例研究Ⅰ:边坡失稳机制模拟分析
发布时间：2019-07-01 19:13
【摘要】：概要介绍龙岩双永高速公路K227超高路堑边坡的地形地貌、地质条件、变形破坏过程及特征,结合边坡稳定度反分析思路、强度折减法和开挖有限元仿真技术对该边坡变形孕育过程进行模拟分析和定量评估。采用一种基于应力张量差值的增减变化及其变化量的正负分区来确定边坡开挖松弛区的数值方法,解释路堑高边坡开挖卸荷松弛的力学机理;模拟重现了挖方边坡经历稳定性缓慢上升的卸荷回弹阶段、稳定性线性下降的剪切破裂阶段和稳定性急剧下降的失稳破坏阶段的全过程中应力调整、塑性屈服、滑面孕育和变形破坏的演化规律和发展趋势,揭示了边坡由于快速工程开挖扰动,使潜在软弱带充分暴露,并切断坡脚力学支撑,伴随岩土卸荷松弛及强度弱化,产生坡顶岩土张裂变形、深层软弱带剪切蠕动和坡脚沿结构面临空剪出的失稳机制;间歇性降雨入渗的岩土增重及附加水压使滑坡表现出时滑时停的特征;边坡整体处于临界状态,在继续开挖或持续暴雨冲击条件下,可能导致稳定性骤降,从滑动阶段转化为剧滑阶段。最后,对应急抢险对策、治理方案规划及线路调整设想等问题进行讨论与反思,为边坡病害治理提供了理论依据。
[Abstract]:This paper briefly introduces the topography and geomorphology, geological conditions, deformation and failure process and characteristics of K227 ultra-high cutting slope of Longyan Shuangyong Expressway. Combined with the idea of back analysis of slope stability, strength reduction method and excavation finite element simulation technology, the deformation preparation process of the slope is simulated, analyzed and quantitatively evaluated. A numerical method based on the increase and decrease of stress tensor difference and its variation is used to determine the excavation relaxation zone of slope excavation, and the mechanical mechanism of excavation unloading relaxation of cutting high slope is explained. The evolution law and development trend of stress adjustment, plastic yield, sliding surface gestation and deformation failure of excavated slope are simulated and reproduced in the whole process of unloading springback stage of slow rise of stability, shear fracture stage of linear decline of stability and instability failure stage of sharp decline of stability. It is revealed that the potential weak zone of slope is fully exposed and the mechanical support of slope foot is cut off due to excavation disturbance of rapid engineering. With the relaxation of rock and soil unloading and the weakening of strength, the tension and crack deformation of rock and soil at the top of the slope, the shear peristalsis of the deep weak zone and the instability mechanism of the slope foot facing empty shear along the structure are produced. The rock and soil weight gain and additional water pressure of intermittent rainfall infiltration make the landslide show the characteristics of sliding and stopping, and the slope as a whole is in a critical state, which may lead to a sudden drop in stability under the condition of continuous excavation or continuous rainstorm impact, which may change from sliding stage to sharp sliding stage. Finally, the emergency countermeasures, treatment scheme planning and line adjustment are discussed and reflected, which provides a theoretical basis for the treatment of slope diseases.
【作者单位】： 福州大学环境与资源学院;地质工程福建省高校工程研究中心;中国公路工程咨询集团有限公司中咨华科交通建设技术有限公司;
【基金】：国家自然科学基金资助项目(41002127) 交通运输部建设科技项目(201331849A130) 福建省交通运输科技项目(201242)~~
【分类号】：U418.5
，
本文编号：2508729
[Abstract]:This paper briefly introduces the topography and geomorphology, geological conditions, deformation and failure process and characteristics of K227 ultra-high cutting slope of Longyan Shuangyong Expressway. Combined with the idea of back analysis of slope stability, strength reduction method and excavation finite element simulation technology, the deformation preparation process of the slope is simulated, analyzed and quantitatively evaluated. A numerical method based on the increase and decrease of stress tensor difference and its variation is used to determine the excavation relaxation zone of slope excavation, and the mechanical mechanism of excavation unloading relaxation of cutting high slope is explained. The evolution law and development trend of stress adjustment, plastic yield, sliding surface gestation and deformation failure of excavated slope are simulated and reproduced in the whole process of unloading springback stage of slow rise of stability, shear fracture stage of linear decline of stability and instability failure stage of sharp decline of stability. It is revealed that the potential weak zone of slope is fully exposed and the mechanical support of slope foot is cut off due to excavation disturbance of rapid engineering. With the relaxation of rock and soil unloading and the weakening of strength, the tension and crack deformation of rock and soil at the top of the slope, the shear peristalsis of the deep weak zone and the instability mechanism of the slope foot facing empty shear along the structure are produced. The rock and soil weight gain and additional water pressure of intermittent rainfall infiltration make the landslide show the characteristics of sliding and stopping, and the slope as a whole is in a critical state, which may lead to a sudden drop in stability under the condition of continuous excavation or continuous rainstorm impact, which may change from sliding stage to sharp sliding stage. Finally, the emergency countermeasures, treatment scheme planning and line adjustment are discussed and reflected, which provides a theoretical basis for the treatment of slope diseases.
【作者单位】： 福州大学环境与资源学院;地质工程福建省高校工程研究中心;中国公路工程咨询集团有限公司中咨华科交通建设技术有限公司;
【基金】：国家自然科学基金资助项目(41002127) 交通运输部建设科技项目(201331849A130) 福建省交通运输科技项目(201242)~~
【分类号】：U418.5
，
本文编号：2508729
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