【作者】 赵文；

【导师】 谢强；

【作者基本信息】 西南交通大学 ， 岩土工程， 2005， 博士

【摘要】 高陡边坡桥基位置不仅关系到高边坡的稳定和桥梁的安全,也直接关系到整个桥梁的技术指标和造价。荷载作用下高陡边坡岩体力学行为特征是桥基位置确定及边坡稳定性分析的基础。本论文对高陡边坡岩体在荷载作用下的力学行为特征进行系统的分析,揭示荷载作用下边坡岩体力学行为特征及变化规律,提出基于岩体力学行为分析的高边坡桥基位置设计及边坡稳定性分析方法,补充完善现有设计理论。 为了便于数值分析,本论文首先开发了适用于高边坡岩体力学行为以及不连续面力学行为分析的接触有限元程序。 对于可视为均质材料的岩体高边坡,对荷载作用下岩体的应力特征和变形特征进行系统分析,对影响边坡岩体力学行为的各种因素进行分析,包括坡度、坡高、荷载强度、桥基位置、桥基宽度、坡型等。揭示了各种影响因素下岩体应力影响范围、坡面岩体应力、桥基位移、基底接触应力等的变化规律。 对层状岩体边坡采用横观各向同性连续介质分析方法进行研究,对层面角度、力学参数这两个影响层状岩体边坡力学行为的主要因素进行分析,揭示了层面角度和力学参数对层状岩体边坡力学行为的影响规律,指出层状岩体不均匀应力分布对坡面岩体应力影响最大的层面角度在20°～30°之间,力学参数的差异体现层状岩体应力受层面角度的影响程度。 利用接触单元法对高陡边坡中普遍存在的卸荷裂隙的影响进行研究,特别是卸荷裂隙深度、卸荷裂隙与桥基的相对位置等对边坡岩体力学行为的影响进行研究。指出卸荷裂隙深度不及应力影响角范围时可不考虑卸荷裂隙的影响,桥基宜置于卸荷裂隙之后,当桥基置于卸荷裂隙之前时,应考虑荷载对坡面和卸荷裂隙的双重影响。 对高陡边坡中存在的长大贯通结构面力学行为特征进行详细分析,根据结构面上的接触应力分布特征确定结构面上各点稳定性系数及整体稳定性系数,提出节理岩体稳定性分析方法,提出荷载作用下岩体边坡潜在破坏面的确定方法。 利用岩体强度与应力影响系数的关系确定应力影响系数的安全限值,根据不同影响因素下边坡岩体应力影响范围的变化规律建立高陡边坡桥基位置确定公式,桥基基本距离S_a=0.0309591α^1.4823[（1-0.8655^B）q]^0.6965。考虑岩体更多还原

【Abstract】 The bridge foundation position on high-steep slope has great effect on stability of slope and bridge; it also affects the technical index and cost of bridge. The mechanical behavior characteristics of rock mass of slope under load are the basis of bridge foundation position determining and slope stability analysis. In this paper, the mechanical behavior characteristics of rock mass of high steep slope under load are analyzed systematically. The regularity of mechanical behavior characteristics of rock mass under load is indicated. The methods of bridge foundation position determining and stability analysis of slope based on mechanical behavior of rock mass are put forward. And the present design theory is improved.For numerical analyzing conveniently, a FEM program suitable to mechanical behavior analysis of rock mass of high-steep slope and discontinuity surface contact analysis is developed.To rock mass slope treated with homogeneous material, the stress and deformation characteristics of rock mass under load are analyzed in detail. The influence factors of rock mass mechanical behavior characteristics are analyzed. The influence factors include slope angle, slope height, load intensity, bridge foundation position, bridge width, slope type etc. The regularities of stress influence range of rock mass, rock mass stress of slope surface, bridge foundation displacement, additional stress of foundation base are denoted.To bedded rock mass, the mechanical behavior characteristics under load are studied with method of transverse isotropy. The main factors which influence the mechanical behavior of bedded rock mass include bedding angle and mechanical parameters. The influence regularities of bedding angle and mechanical parameters on mechanical behavior of bedded rock mass are denoted. The result shows that the most disadvantageous bedding angle is between 20° and 30°, and the difference of mechanical parameters indicates the influence degree of bedding angle on rock mass stress.The influence of relaxed crack of high steep slope on mechanical behavior characteristics of rock mass is studied. Especially the influences of the height of relaxed crack, the relative position between relaxed crack and bridge foundation on mechanical behavior of rock mass are analyzed in detail. The results show that if the height of relaxed crack is out range of the stress diffusion angle, the influence of relaxed crack can be ignored. The preferredposition of bridge foundation is behind of the relaxed crack. While the bridge foundation set before the relaxed crack, the both influence of slope surface and relaxed crack should be taken into account.The mechanical behavior characteristics of long-through structural plane on high steep slope are analyzed in detail. The stability of long-through structural plane is determined according to the contact stress of structural plane. The methods of stability analysis of jointed rock mass and determining method of potential failure surface of slope under load are put forward.The safe influence coefficient of stress is determined according to the relation between rock mass strength and influence coefficient of stress. According to the regularities of rock mass mechanical behavior characteristics of different influence factors, the basic distance of bridge foundation on high-steep slope is determined as follow:Sa=0.0309591a14823[(l-0.8655B)#6965While considered the rock mass quantity, the distance of bridge foundation on homogeneous slope is determined as S/=Sa-ksr. The distance of bridge foundation on stratification slope is determined as S/=Sa-ks^-ksr. The methods determining the bridge foundation position in special situation are put forward, such as polygonal line slope, relaxed crack slope, long-through structural plane slope and so on.Take Beipanjiang river bridge project as an example, the bridge foundation position is determined by method of this paper. The mechanical behavior characteristics of rock mass under load are analyzed in detail. The collapse stability and slip stability of jointed rock mass are analyzed. The results show that the slope is stable under load at the bridge foundation position determined by method of this paper, and the position of bridge foundation is rational. For verifying the rationality of the method determining bridge foundation of this paper, the displacement character and failure pattern of the slope are studied with model test, DEM and field monitoring. The results prove that the methods determining position of bridge foundation and the stability analysis method of jointed rock mass in this paper are rational.The bridge foundation position determining method put forward in this paper supports by abundant and clear theory. Applying this method to engineering practices, the economical value will be remarkable.更多还原