【作者】 钟卫；

【导师】 周德培；

【作者基本信息】 西南交通大学 ， 岩土工程， 2009， 博士

【摘要】 水电工程的修建过程中,经常会碰到复杂岩质边坡开挖稳定性问题。本文以世界第一高拱坝-锦屏一级水电站为依托工程,从工程地质调查分析入手,提出了高地应力区复杂岩质边坡坡体结构的概念、类型划分及其相应的破坏模式；根据实测的“点”地应力成果,回归反演了坝区的“场”地应力,在此基础上研究了回归地应力施加到计算模型上的方法；分析了边坡开挖的地应力释放规律,利用定性和定量方法对开挖引起的二次应力分区进行了研究,据此分析了边坡稳定性分析中的地应力考虑；然后根据损伤力学理论和岩石经验强度准则,推导了新的岩石统计损伤本构模型,再利用其强度折减原理,提出边坡考虑回归地应力的数值模拟方法以及基于变形-应力场的三维点安全系数法来评价边坡的稳定性；对坡体内含多组贯通结构面的块体组合,运用块体理论编制了相应的计算程序；最后通过现场监测成果,进行了三维监测反馈分析。论文在理论研究的同时,注重应用和试验验证,将研究成果应用于实际工程,接受实际工程的检验。主要取得了如下研究成果：(1)高地应力地区复杂岩质边坡坡体结构的概念、类型及其相应失稳破坏模式的确定。对比岩体结构、边坡结构的概念,提出了高地应力地区坡体结构的概念。在总结变形破坏模式和失稳机理的基础上,将坡体结构分为6个大类,并对在坡体内常见的发育1-3组节理的节理控制式坡体结构进行了亚类划分,初步建立起基于坡体结构的高地应力区复杂岩质边坡稳定性分析方法；(2)考虑河谷下切及地表剥蚀的区域地应力场回归。分析了坡体地应力的一般影响因素及深切河谷地区的地表剥蚀及河谷下切的特殊影响因素,根据实测的点应力,利用多元线性回归,得到了工程中可以利用的场应力,总结了深切河谷地区地应力场的分布规律,建立了从回归场应力到计算模型应力的施加方法；(3)边坡开挖引起的二次应力调整分析及边坡稳定性分析中构造应力的考虑。通过分析边坡开挖引起的地应力释放特点,从定性和定量两个方面分析边坡开挖引起的二次应力分区,在此基础上分析了边坡开挖稳定性中构造应力的考虑；(4)边坡开挖稳定性分析中考虑回归地应力的数值模拟方法。根据第1和第2提出的方法建立计算模型及确定模型上的地应力,基于损伤力学及岩石破坏的经验强度准则,通过室内岩石物理力学特性试验,推导了新的岩石损伤本构模型及损伤演化方程,并以FLAC3D为开发平台,利用其内嵌的FISH语言,编制了数据接口程序,在数值计算中反映了岩石破坏的损伤演化过程,从而确定出边坡的潜在破裂面,在此基础上,提出基于单元变形-应力场的三维点安全系数法来评价边坡的开挖稳定性；(5)编制了基于块体理论的岩质边坡三维块体稳定性分析程序。对于坡体内含多组贯通结构面的块体组合,根据块体理论的基本知识,利用程序语言编制了三维块体稳定性分析程序,解决了多结构面组合形成的临界失稳块体,特别是半确定性块体及随机块体中临界失稳块体的确定问题；(6)边坡的三维监测反馈分析。根据已获得的地质资料和岩石物理力学试验结果,结合计算域实际情况分析,确定待反演参数的变化范围,利用正交试验设计数值模拟方案,采用FLAC3D计算每组模拟方案对应边坡监测点的位移值。根据边坡监测点的位移值与各种参数方案所对应的计算值之间的函数关系(接近程度),确定出与计算模型范围和边界条件相适应的最佳计算参数,最后根据参数反演结果进行了开挖变形的正分析,参数的反演结果可以为数值计算和块体稳定性分析提供相应的参考。更多还原

【Abstract】 The problem of excavation stability on complex rock slope is frequently encounted in the course of hydropower engineering construction. Thus, this paper will concentrate on the above topic based on the project-JinPing I stage hydropower station-the highest arch dam in the world. Started from the analysis of geological survey in engineering, the concept, classifications as well as the corresponding failure modes of the slope structure of complex rock slope are summarized in areas with high field stress. The field in-situ stress of dam area is inversed with regressive analysis method according to the actual measurement results toward several points. And on the basis the applied method from regressive ground stress to calculation model is studied. Furthermore, the release rules of ground stress caused by slope excavation are analyzed. And the corresponding secondary stress divisions are made by using qualitative and quantitative method. Hereby the condsideration of ground stress in the slope stability is analyzed. Then based on damage mechanics theory and rock empirical strength criterion, new statistical damage constitutive model of rock is derived. By using its strength reduction principle, the numerical simulation method considering regressive ground stress and three-dimensional point safety factor method based on deformation-stress field are put forward to evaluate the excavation stability of slope. As for block combinations including multi-group transfixion structure surface in the slope mass, corresponding calculation program is compiled by using block theory. Finally, three-dimensional monitoring feedback analysis is made by field monitoring results. While theoretical research is made, the application of the theory to practical engineering and checks for the legitimacy of the theoretical results compared with practice are important part in this thesis. The following is the research contents.(1) The determination about concept, types and its corresponding instability failure mode of slope mass structure of complex rock slop at high field stress areas. Compared with rock mass structure and slope structure, the concept of slope mass structure is put forward at high field stress areas. Based on the summarization of deformation and failure mode and instability mechanism, slope mass structure is divided into six large classes. And subclass is made to this slope mass structure commonly developed 1-3 group joints in slope mass. The method of the stability analysis of complex rock slope based on slope mass structure is preliminary established.(2) The regression of initial stress field considering cutting valley and wastage. The influence factors of ground stress and special factors of cutting valley and wastage at deep-incised valley areas are analyzed. According to actual measured point stress and using multivariate linear regression analysis, the field stress which can be used in engineering is gained. The distribution regular of gound stress field at deep-incised valley areas is summarized. The precise method of stress field from regression to calculation model is built.(3) The analysis of secondary stress adjustment caused by slope excavation and the consideration of tectonic stress in slope stability analysis. By analyzing releasing characteristic of groud stress caused by slope excavation, the zones of secondary stress are analyzed from qualitative and quantitative two sides. On the basis, the consideration of ground stress in slope excavation stability is analyzed.(4) The numerical simulation method considering regressive initial stress in slope excavation stability analysis. According to the method which is put forward in the first and second, the calculation model is built and the initial ground stress in model is defined. Based on damage mechanics and the empirical strength criterion of rock failure, by the laboratory test of rock physical mechanics properties, new rock damage constitutive model and damage evolution equation are derived. Taking FLAC3D as development platform and using its embedded FISH language, the data interface program is compiled. The damage evolvement process of rock failure is reflected in numerical calculation. So the potential failure surface of slope is defined. On the basis, the three-dimensional point safety factor method based on deformation-stress field is put forward to evaluate the excavation stability of slope.(5) The three-dimensional block stability analysis program of rock slope based on block theory is compiled. As to the block combination including multi-group transfixion structure in slope mass, according to the basic knowledge of block theory, three-dimensional block stability analysis program is compiled by using programming language. The problem of the determination of potential instability block formed by muti-group structure surface combination is solved, especially in the semi-deterministic blocks and random block.(6) Three-dimensional monitoring feedback analysis of slope. On the basis of the gained geological data and test of rock physical mechanics properties, according to practical situation of the computational domain, the range of waiting for inversion parameters is determined, design scheme of numerical simulation by using orthogonal test, and the displacement of every scheme corresponding monitoring point is calculated by FLAC3D. In accordance to the functional relationship (scilicet degree of closeness) between the displacement of slope monitoring point and the corresponding calculated value of every scheme, the optimum calculation parameters complying with the range of calculation model and boundary is determined. Finally, the face analysis of excavation deformation is done by the result of parameter inversion, which can provide corresponding reference to numerical calculation and block stability analysis.更多还原