宝华镇南北通道路堑碎裂岩体边坡稳定性评价

发布时间：2018-09-05 09:29

【摘要】：近年来,随着工程建设数量不断增多,规模也越来越庞大,人类对山体边坡的改造、利用也日益增多。但是由于山体边坡,特别是碎裂岩体边坡,其性质与土质边坡和其它岩质边坡不同,再加上对碎裂岩体边坡认识的局限性,在施工过程中或施工完成后,碎裂岩体容易发生风化和降水快速入渗,可能再次诱发边坡失稳。因此,需要对碎裂岩体边坡进行全面的认识,针对不同地层、岩性、风化破碎程度的碎裂岩体边坡,确定其破坏模式,进行多种工况的稳定性评价,从而提出对应的治理方案。本文将宝华镇南北通道路堑碎裂岩体边坡作为研究对象,根据该段特殊的地形地貌、水文地质条件,进行工程地质分区和亚区划分,对亚区内不同类型的碎裂岩体边坡进行工程地质分析,确定极软岩边坡的滑动面,引入可靠度理论进行反分析,从而得到结构面的强度参数。本文的主要认识及研究成果如下:(1)通过现场工程地质勘查,对宝华镇南北通道路堑碎裂岩体边坡工程地质分析,确定各地层的岩性及地层间的差异性,进行工程地质分区和亚区划分。(2)根据碎裂岩体边坡所发生破坏部位的不同,将碎裂岩体边坡的破坏模式分为浅表崩塌破坏及坡体深层滑动破坏。对亚区应用节理统计、软件分析等方法,确定各亚区的碎裂岩体边坡具体破坏模式,并提出可行的治理方案。(3)根据龙潭组及孤峰组边坡岩体破碎性质软弱的特点,将其概化为类土质边坡,假定其发生圆弧滑动,采用极限平衡理论对其稳定性进行分析,多段边坡稳定性安全系数接近极限平衡状态,沿着圆弧滑动面发生整体滑动。虽然其中有两个台阶未发生滑动时,其稳定性系数大于1,但是由于模拟时此边坡仍处于卸荷阶段,此岩体的渗透系数较小,降雨入渗尚未达到坡体内部,在计算时没有考虑到降雨作用,但是此种边坡处于稳定状态只是暂时的,因此该种情况也是非常危险的。总体来看,龙潭组及孤峰组地层构成的破碎岩体边坡整体稳定性较差,处于不稳定状态。(4)运用可靠度理论和破坏概率法对高家边组泥岩楔形体破坏边坡进行反分析,得出临界状态边坡岩体的力学强度参数,计算结果表明,以破坏概率给出的结构面力学参数更加符合工程的实际情况,可以供防治工程设计使用。
[Abstract]:In recent years, with the increasing number and scale of engineering construction, the utilization of mountain slope is increasing day by day. However, because the nature of mountain slope, especially broken rock slope, is different from that of soil slope and other rock slope, in addition to the limitation of understanding of broken rock slope, in the process of construction or after the completion of construction, the nature of mountain slope is different from that of soil slope and other rock slope. The fractured rock mass is prone to weathering and rapid infiltration of precipitation, which may induce slope instability again. Therefore, it is necessary to make a comprehensive understanding of the fractured rock slope, to determine the failure mode of the fractured rock slope with different strata, lithology and weathering degree, to evaluate the stability of various working conditions, and to put forward the corresponding treatment scheme. In this paper, according to the special terrain and geomorphology, hydrogeological conditions, engineering geological zoning and subarea division are carried out on the slope of fractured rock mass in the north and south passageway of Baohua town. The engineering geological analysis of different types of fractured rock slope in the sub-area is carried out to determine the sliding surface of the extreme soft rock slope, and the reliability theory is introduced to carry out the back analysis, so as to obtain the strength parameters of the structural plane. The main knowledge and research results of this paper are as follows: (1) through the field engineering geological survey, the engineering geology analysis of the rock slope in the north and south passageway of Baohua town is carried out, and the lithology and the difference between the strata are determined. (2) according to the different failure sites of the fractured rock slope, the failure mode of the fractured rock slope is divided into shallow collapse failure and deep sliding failure. By using the methods of joint statistics and software analysis, the concrete failure mode of broken rock slope in each subregion is determined, and the feasible treatment scheme is put forward. (3) according to the characteristics of the broken rock mass of Longtan formation and Gufeng formation, the rock mass is weak. The stability of the slope is analyzed by the limit equilibrium theory. The safety factor of the multi-section slope is close to the limit equilibrium state and the whole slip occurs along the arc sliding surface. Although the stability coefficient of the slope is greater than 1 when two of the steps are not sliding, the permeability coefficient of the rock mass is small because the slope is still in the unloading stage when the slope is simulated, and the rainfall infiltration has not reached the inside part of the slope. Rainfall is not taken into account in the calculation, but the stability of the slope is only temporary, so the situation is very dangerous. As a whole, the fractured rock slope composed of Longtan formation and Gufeng formation is in a unstable state because of its poor overall stability. (4) using reliability theory and failure probability method, back analysis of the wedge failure slope of high Jiabian formation mudstone is carried out. The mechanical strength parameters of critical slope rock mass are obtained. The calculated results show that the mechanical parameters of the structural plane given by the failure probability are more in line with the actual conditions of the engineering and can be used in the design of the prevention and cure project.
【学位授予单位】：南京大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U416.1

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