【作者】 杨明；

【导师】 张可能；

【作者基本信息】 中南大学 ， 地质工程， 2009， 博士

【摘要】 地质体有别于一般工程材料的一个重要特征就是其中包含有各种具有宏观尺度规模的界面,这种与周围岩体具有显著性质差异的界面在地质上统称为“结构面”,如断层、节理、软弱夹层或岩带、层面等。结构面在很大程度上破坏了岩体的连续性,并控制了岩体的工程地质特性。通过对岩体结构面的力学性质研究,明确岩体在各种荷载作用下结构面变形与强度所产生的力学效应,具有重要意义。论文通过收集前人资料、理论分析、现场试验及数值仿真技术,对结构面力学和变形特性,及在锚杆加固情况下结构面的响应特征、岩体边坡稳定性等相关方面进行了系统的研究,为工程实践提供科学指导。现有岩体结构面剪切应力和剪切位移描述模型的局限性是只能反映塑性结构面的应力变形特征,本文通过对其进行修正,使其即能描述塑性结构面的应力变形特征也能描述脆性结构面的应力变形特征。FLAC3D中锚杆单元只能考虑轴向力和轴向摩擦力的作用,而无法考虑锚杆的横向剪切力作用。在实际节理岩体中,由于节理结构面的错动,往往对锚杆形成横向剪切力,因此,考虑锚杆的横向剪切力特征显得较为重要,本文对FLAC3D的锚杆单元进行修正,通过内置的FISH语言实现更加符合实际情况的锚杆数值单元。通过现场锚杆拉拔试验,对不同锚杆锚头位移与锚头拉力之间的关系进行了分析,同时利用修正的FLAC3D的锚杆单元进行数值模拟计算,锚头位移与锚头拉力之间的计算关系曲线与实测的结果基本一致,从而验证了本文所建立的锚杆修正单元的正确性。另外,通过自行编制ANSYS-FLAC3D的转换程序,改进以往文献中所编制程序的ANSYS-FLAC3D的数据导入方法,使数据导入速度和建模效率得到大大提高,从而实现了复杂表面形态结构面试样模型的数值建立。同时,论文探讨了结构面形态对于剪切强度和应力应变关系以及结构面破坏模式的影响,建立了结构面起伏角与结构面剪切强度之间的关系模型；探讨了硬性结构面的数值实现方法,并研究了法向位移和剪切位移的关系,揭示了结构面剪胀特性,并建立了剪胀理论模型；研究了结构面加载过程中,加载速率对结构面剪切强度的影响,并建立了二者之间的线性拟合模型。也探讨了节理试样剪切强度与节理面厚度的关系,并针对不同起伏角,建立二者关系曲线的二次抛物线拟合方程。鉴于在加锚条件下结构面的应力和变形特征研究的不足,本文通过数值模拟的方法,并利用第二章所建立的修正的锚杆单元,分别对比了结构面在加锚和无锚情况下的强度特征,应力应变特性,并研究在不同锚杆倾角情况下,结构面的力学和变形行为。为了进行节理岩体边坡锚杆加固的优化研究,探讨了锚杆参数,如长度,倾角,间距对于节理边坡稳定性的影响,并建立了它们之间的关系模型,得到的结果可以为工程实践提供重要指导。更多还原

【Abstract】 Geological material is different from other materials, for it contains many different size interfaces, which are named structure plane like fault, joint, weakness plane and stratified plane etc. They break the continuous of the rock mass, and control the geological characteristic of rock mass. So it is meaningful to study the mechanical characterisitic of rock mass structure plane, and its mechanical effect induced by the different loading.The mechanical and deformation characterisitic of structure plane, the response of structure plane with bolt reinforcement, joint rock slope stability and joint rock slope with bolt reinforcement are studied in the present thesis, according to the method of theoretical analysis, insitu-test and the numerical calculation method. The results of the present thesis can give some guidance for the real project.The existed model for describing the relationship between shear stress and shear displacement of structure plane can only reflect the type of plastic structure plane, so this model is modified in the present thesis, which can then describe the stress deformation characteristic of both the plastic and brittle stucture plane.The bolt element in FLAC3D can only reflect the effect of axial stress and axial friction stress, but in reality, the bolt also sustains the shear stress in the normal direction. So it is important to consider the shear stress in the normal direction of bolt, especially for structure plane reinforced by bolt. The bolt element in FLAC3D is modiefied by the internal FISH language, to make it more close to the real situation.According to the insitu-test of bolt with tensile stress, the relationship between the bolt head displacement and the tensile stress are analyzed. Then the bolt tensile test is modelled by the numerical calculation method, in which the modified bolt element is used. The comparisons are done for the results obtained from the insitu-test and the numerical analysis method, which validates the correctness of the modified bolt element done in the present thesis. The data transferring program from ANSYS to FLAC3D is compiled, in which the data transferring method is different from those in other papers, the data transferring method can greatly increase the data transffering effeciency, and the complicated suface for structure plane can be modelled by this program.The shear strength, stress-strain relationship and the failure mode of structure plane are analyzed. The theoretical models are founded for them. The method useing interface to model the structure plane is analyzed, the relationship between the normal displacement and shear displacement is studied, which shows the shear dilatant characteristic of structure plane, and the shear dilatant theoretical model is founded. The effect of the shear velocity to the shear strength of structure plane is studied, and there fitting model is built.The relationsip between the shear strength and the joint thickness is analyzed, the fitting equations are founded for them with different roughness angles.The characteristic of stress and deformation of structure plane with bolt reinforcement are seldom studied in the existing material. But in the present thesis, this problem is studied by the numerical simulation method, in which the modified bolt element is used. The strength characteristic and stress-strain characteristic are compared for the situations of structure plane with the without bolt reinforcement of different inclination.In order to do the optimal study for the joint rock slope with bolt reinforcement, the effect of bolt parameters like bolt length, bolt inclination and bolt spacing to the stability of joint slope are studied, whose results can give some guidance for the real project.更多还原