【作者】 何晖；

【导师】 杨更社；

【作者基本信息】 西安科技大学 ， 岩土工程， 2013， 博士

【摘要】 微型桩在滑坡防治中一经使用便得到学术界及工程界广泛关注，微型桩的桩径较小、长径比大、抗弯刚度小，其应用历史短，人们对它的承载机理和破坏模式还没有充分认识，其对滑坡的加固补强作用如何发挥，微型桩组合结构如何抗滑、加固，目前的研究分析还不够深入，尚没有形成一套比较系统的微型桩计算理论和设计方法，很大程度上仍然影响着微型桩的应用与推广。因此研究微型桩的承载、变形及破坏机理及微型桩的设计理论和工程应用技术，发展符合实际工程特点的微型桩设计理论及施工技术显得十分重要。陕南山区处于我国秦巴山地之中，地质构造复杂，岩体破碎，气候特殊，是我国地质灾害高发区和重灾区。全区共发育地质灾害7109处，其中滑坡6353处，占总数的89.4%，对区内3442处滑坡灾害调查数据统计分析后发现，滑坡中堆积层滑坡约占总数92.3%，堆积层滑坡中浅层滑坡占51%，中层滑坡占42%，深层滑坡占7%，部分滑坡具有膨胀性。滑坡灾害防治成为地方政府的一项重要任务。论文依托《陕南山区滑坡灾害防治关键技术研究》项目，以陕南地区具有明显区域特征的滑坡体和不同组类的微型抗滑桩为主要研究对象，首先从滑坡滑体厚度、滑面倾角、滑体规模、滑体岩性、稳定性状态和形成机理六个方面提出了复杂地质环境条件下陕南山区堆积层滑坡的分类方案，研究了降雨入渗诱发堆积层滑坡形成机理和具有膨胀性的堆积层滑坡形成、破坏机理。以室内相似模型试验、数值分析、工程现场监测试验、微型桩应用工程总结分析为手段，对微型桩加固堆积层膨胀土滑坡的荷载传递路线、荷载分配规律、微型桩受力、变形特性和破坏模式进行系统研究，分析微型桩在不同桩间距、排间距、锚固深度、桩顶约束及大气降水等因素影响下的承载特点，研究微型桩对膨胀土滑坡的加固机理、设计原则和设计技术。研究内容对陕南山区滑坡灾害微型桩治理的设计理论及施工技术进步有着重要的理论与实践意义。论文取得的研究成果为：（1）本文首次提出了复杂地质环境条件下陕南山区堆积层滑坡的分类方案，并分析了陕南堆积层滑坡的发育特征和影响因素，研究了降雨入渗诱发的堆积层滑坡和浅层膨胀土滑坡的形成、破坏机理。（2）利用数值模拟、物理模型试验、现场监测试验手段，首次对陕南山区浅层堆积层膨胀土滑坡微型桩加固机理进行了系统的研究。（3）对桩的合理间距、合理排拒、桩土共同作用、排桩荷载分担比、桩的锚固深度、连系梁的作用及敏感因素分析并结合降雨情况进行了研究，结合22个滑坡工程的设计实践，确定了微型桩的三种破坏模式，分别为整体破坏、单桩破坏和局部破坏，首次提出了陕南山区浅层堆积层膨胀土滑坡微型桩加固的设计原则、设计思想、设计方法和设计步骤。更多还原

【Abstract】 Once micropile has been used in landslide reinforcement, it immediately gains its concern form the academic and engineering circles because of its small pile diameter, quite large lenth-diameter ratio, and its small flexural rigidity, however, due to its short time application, its bearing mechanism and failure modes are not fully grasped in depth, especially the research on how to develop the roles of micropile reinforcement on landslide, and the ways in which composite structure of micropile works on anti-slide and reinforcement are not plenitudinous. Furthermore, there is not a relatively comprehensive theoretical system of micropile calculation and design method, which largely affects the application and promotion of micropiles. Therefore, it is really important to study on load of supporting, deformation, failure modes of micropile, design theory, engineering application technology and construction technology in line with practical engineering.South mountainous region of Shaanxi Province lies in Qinba mountains in China well known for its complex geological structure, rock mass crushing, and special climate, which make it to be a high incidence zone of geological disasters and the landslide prone and worst-hit areas in China. In total, there are7109geological disasters in the area including6353landslide disasters which accounts for89.4%of the total. Based on a statistical analysis of survey of3442landslide disasters, it is found that shallow landslide accounts for51%, middle type makes up for42%, deep slide7%, and part of expansive soil landslide. For this reason, Landslide disaster prevention has become an important task for local governments.Based on the project named "A study on the key technology of prevention and control of landslides in Southern mountainous region of Shaanxi Province", and with different types of landslides characterized by region geographical features and anti-sliding piles as the main research object, this paper first puts forward the categories of accumulative landslide under complex geological environmental conditions in south mountainous region of Shaanxi Province from six aspects such as thickness of landslide body, angle of landslide, size of landslide, lithology, stability and its formation mechanism. And then it carefully probes genetic mechanism for rainfall induced accumulative landslide, the formation of expansive accumulative landslide and its failure modes. Later, it systematically analyzes of load transfer of micropile strengthening accumulation of expansive soil landslide, load distribution rule, the stress, deformation characteristics and failure modes by numerical simulations, in-door physical model test and on-site monitoring test, summary of micropile engineering application. And it also analyzes the load-bearing characteristics of micropile under the influence of the factors such as different pile spacing, row spacing, anchorage depth, pile top restraint, and rainfalls, while its reinforcement mechanism, design principles and design techniques on expansive soil landslides are further discussed. Therefore, the research attaches theoretical and practical importance to design theory of micro pile treatment for landslide hazards in southern mountain areas and development of in-site construction technology.Major findings go as follows:1. This paper first presents the categories of accumulative landslide under complex geological environmental conditions in South mountainous region of Shaanxi Province, and then analyzes the development characteristics and factors of accumulative landslide, and also probes formation and failure mechanism of landslide caused by rainfall induced, and shallow expansive soil.2. By means of numerical simulations, physical model test, on-site monitoring test, a systematic study on the reinforcement mechanism of micropiles on the shallow accumulation layer of expansive soil landslide in mountainous areas in southern Shaanxi was made.3. Reasonable pile spacing, row spacing, pile-soil interaction and row pile load-sharing ratio, anchorage depth, even the effect of tie beam and analysis of sensitive factors combined with rainfall patterns have been studied, and the design on22accumulative landslides were made,3failure modes of micropile structure were put forward, then the design principle, design thought, design method and design processes of reinforcement of micropiles working on accumulative landslides of expansive soils in southern mountainous region of Shaanxi Province was first proposed.更多还原