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巨型滑坡失稳特征及针对性防治技术研究
Alternative TitleInstability Characteristics and Targeted Control Technology of Gigantic Landslide
陈剑
Subtype博士
Thesis Advisor王全才
2017
Degree Grantor中国科学院大学
Place of Conferral北京
Degree Discipline岩土工程
Keyword巨型滑坡 失稳规律 滑坡推力 集成式防治结构 前缘治理技术
Abstract巨型滑坡对大型基础建设工程危害大,必须采取针对性防治技术实施绕避或治理方案。由于缺少对巨型滑坡特征的清晰认识,工程建设中将场址误选在古老巨型滑体之上,给后期治理造成极大困难。治理中由于对巨型滑坡滑带土强度不均性、地下水分布复杂性、前缘土体松散富水性等特点的针对性不足,导致了工程治理失败。针对以上问题,在总结分析前人对巨型滑坡防治技术成果基础之上,开展了以下4个方面的研究工作:分析了我国巨型滑坡的基本特征和时空发育规律;给出了抗滑桩设计推力计算方法;提出了一种集排水、抗滑、抗震和防冲击功能的集成式新型防治结构,基于流-固耦合理论对其排水抗滑能力进行研究,通过理论计算及现场试验,给出了新型防治结构的优化设计及计算方法;提出了巨型滑坡前缘三层立体式综合治理方案并给出了其相应的计算方法。研究成果对巨型滑坡防治具有重要的理论意义,可为巨型滑坡治理工程提供实用参考。取得的主要研究成果如下:1. 总结了巨型滑坡的基本特征及治理工程布置要点,初步揭示了我国巨型滑坡的空间分布规律详细研究了巨型滑坡的基本特征,根据不同变形破坏类型给出工程治理布置要点,划分了我国巨型滑坡发育的3个集中分布带:长江上游分布带、黄河上游分布带和龙门山断裂分布带。2. 探讨了巨型滑坡不同时间尺度下的周期性失稳规律气候暖期、冷期向暖期的过渡期是巨型滑坡失稳的高发期;巨型滑坡具有近11年的长周期性失稳规律,在太阳黑子相对数下降期内巨型滑坡失稳数量和强度均显著高于上升期;巨型滑坡具有15天的短周期性失稳规律,且非暴雨型滑坡在朔望日附近时段的失稳概率最大。引力计算表明,太阳和月球引力作用对滑坡的激发具有规模效应。3. 推导了巨型滑坡滑带抗剪强度参数连续分段取值的量化公式,给出了考虑桩土耦合作用的滑坡推力计算方法在滑带土本构方程基础上,引入渐变软化段位置函数f(t)和规模放大系数λ反应实际滑带土的时效性和空间变异性,提出了基于监测位移确定各点滑带土强度的量化方法。考虑桩土耦合作用的滑坡推力计算方法,所求解的滑坡推力介于传统不平衡推力法的显示解和隐示解之间,设桩处滑面倾角a和安全系数Ks是影响抗滑桩设计推力的两大关键因素。4. 提出了集排水、抗滑、抗震和防冲击功能的集成式巨型滑坡新型防治结构,基于流-固耦合理论对传统结构和新型结构的排水抗滑性能进行对比研究提出了由锚索抗滑桩、挡土板、渗水材料和导水洞等结构组成的集成式滑坡治理新型防治结构。基于流-固耦合理论,对比研究了传统防治结构(锚索抗滑桩+泄水隧洞)与新型防治结构支护下滑坡的排水抗滑性能。研究表明,在新型防治结构支护下,坡体长期排水性能较好,坡体最大剪应力、结构的最大剪应力和最大位移以及锚索最大轴力均低于传统防治结构支护下的相应值,综合表明了新型防治结构的优越性。5. 基于弹性地基梁理论,给出了锚索抗滑桩的优化设计方法,采用现场拉拔试验给出了多重锁固外锚头的优化设计参数基于弹性地基梁理论和变形协调条件,给出了锚索预应力以及抗滑桩桩身内力的优化计算方法。通过试验得出多重锁固外锚头的推荐设计方法:锚固胶厚度4-5mm、钢套筒横内纹处理、端头刺钉膨粗,钢套筒长度根据锚索预应力值及钢绞线数量综合确定;地震区可在夹片与钢套筒间设计弹簧以防止地震作用下锚索因往复运动而破坏,在滚石区或意外抛掷物较多的地区建议采用内嵌式封锚技术。6. 针对巨型滑坡前缘地形高陡、岩土破碎松散等特点,提出了三层立体式防冲固坡综合方案,并给出了相应的设计计算方法提出了水下护坡四面体、桩顶墙和固坡桩三种前缘治理技术,理论计算表明:水下护坡四面体设计尺寸与水流速度的平方成正比关系。采用弱性连接的桩顶墙结构能够降低作用于挡墙的墙背压力,同时可减小传递至下部结构的剪力和弯矩。固坡桩结构具有局部增大结构刚度的作用,且存在一个最优伴桩率,在最优伴桩率下桩顶位移最低。
Other AbstractAs the gigantic landslide could cause fatal damages on a large of infrastructure projects, necessary measures and control technology must be taken for implement or avoidance. Due to the lack of well understanding on the basic characteristics of gigantic landslide, the mis-selections of engineering project sites on ancient gigantic landslide body would cause great difficulties in late treatment. During the treatments, the lack of pertinence about the inhomogeneous strength of the sliding zone soil, complex distribution of groundwater and the landslide toe soils exhibiting loose and water enrichment induced the treatment to be failed. Based on the above-mentioned common problems in practical engineerings, this study summarized predecessors' research results about the prevention and control technology on gigantic landslides, and the following works were carried out: Firstly, the basic characteristics and time-spatial developmental laws of gigantic landslides were deeply analyzed. Secondly in-depth research on calculations on thrust for anti-slide pile design was carried out. Thirdly a new type of prevention structure, which combined drainage, anti-slide, earthquake and impact resistant, had been proposed. Additionally, on the basis of the fluid-solid interaction theory, drainage and anti-sliding ability of the new prevention structure were researched, and the theoretical calculation and filed test were applied to emphasize on the optimization design and calculation methods. Forthly, a comprehensive control scheme of three-layer vertical erosion prevention and consolidating on gigantic landslide front edge and its corresponding calculation method were proposed. The results well showed great significances on the prevention and control of gigantic landslides, and can provide helpful and practical reference for gigantic landslide remediation. The main conclusions of this study are listed as follows:1. The basic characteristics of gigantic landslides and key layout points of landslide control engineering were described, and the spatial distribution laws of gigantic landslides in China were listed.In this research, a detailed analysis was conducted on the basic characteristics of gigantic landslides. Based on different types of deformations and failure, the key layout points on retreatments of gigantic landslides were proposed. The gigantic landslides in China could be divided into three concentrated zones: Yangtze River upriver-, Yellow River upriver-, and Longmenshan fault- distribution zone.2. The periodic instability laws of the gigantic landslides under different time scales were explored.Gigantic landslide instability would enhance in the interglacial epoch and the transition period of glacial to interglacial epoch. There was a long periodic instability law of gigantic landslide which was featured with nearly 11 years, and it was significantly higher during the declining stage of relative sunspot numbers than the rising stage for the number and intensity of instability of gigantic landslides. In addition, a short periodic instability law of gigantic landslide could also be found out, which was nearly 15 days, and during the syzygy period, the instability probability of gigantic landslides was the highest. The calculations on gravity resulted that the sun and the moon gravity had scale effect on the excitation of gigantic landslides.3. The quantitative formula for calculating continuous strength parameters of gigantic landslide sliding soil were deduced, and a comprehensive calculations on landslide thrust considering the soil-pile interaction was carried out.Based on the constitutive equation of sliding soil, the position function of the gradual soften part f (t) and scale modification coefficient λ were introduced to well consider the actual reaction of timeliness and spatial variability of sliding soil, and according to slope displacement monitoring, the quantitative analysis on determining the shear strength of sliding soil was put forward. Furthermore, as for the calculation method of landslide thrust considering the soil-pile interaction, the solutions were between the explicit solutions and implicit solutions of traditional imbalance thrust force method. The calculation results showed that, the inclination angle of slip surface a and the safety coefficient Ks, were the most important affecting factors for the design thrust for anti-slide pile.4. A new gigantic landslide prevention structure was proposed, which comprehensively considering the drainage, sliding resistance, earthquake and impact resistant. A comparison analysis on drainage and anti-sliding performance between the traditional and the new structure were conducted based on fluid-solid interaction theory.A new integrated structure for controlling landslides, mainly consisting of anti-slide pile, soil retaining plate, permeable materials and discharge tunnel, was put forward. Relying on the fluid-solid interaction theory, the analysis on anti-sliding and drainage performance of traditional structure (which contains anti-slide pile and drainage tunnel) were compared with the new structures. The calculation results showed that the new structure exhibited well performance on long-term drainage. With the application of new structure, the maximum shear stress of slope, the maximum stress of the structures, the maximum displacement, and maximum axial force of the anchor cable were lower than the corresponding values of traditional structures, which well showed the superiority of the new structure in landslide treatment.5. Based on the elastic foundation beam theory, the optimization scheme on anchor anti-slide pile design was proposed, further, the pull-off tests on field were performed as an important tool to offer the parameters for optimization design on multiple locking anchor head.Based on the elastic foundation beam theory and deformation compatibility, the calculation on pre-stress of anchor cable and internal force of anti-slide pile were optimized. Relying on pull-off tests on field, optimized parameters of multiple locking anchor head were preferred: 4-5 mm for the thickness of anchor glue, the transverse grain processing for steel sleeve interior and setting barbed nail on the end. Steel sleeve length could be determined through the comprehensive analysis on pre-stress of anchor cable and the numbers of steel strand. In terms of the earthquake prone area, the spring could be installed between the clip and steel sleeve, which can prevent the earthquake damage due to reciprocating motion of anchor cable. In rockfall impact zone, embedded anchor technology was recommended. 6. Against the gigantic landslide toe, which is characterized with high and steep terrain, and with crush and loose condition of soil and rock, it came up with a comprehensive remedial scheme of three-layer vertical erosion prevention and solidification, and its relative calculation methods.The retrofitting measures on gigantic landslide toe, including tetrahedron for underwater slope protection, the pile-underpinning-wall structure, partial double-row piles structure, were proposed. The theoretical analysis showed that, the design size of tetrahedron for underwater slope protection was proportional to the square of flow speed. The application of pile-underpinning-wall structure with weak connection could lower the back pressure acting on retaining wall, as well as the shear force and bending moment transmitted to the substructures simultaneously. As for the partial double-row piles structure, it could increase the local structure stiffness, and under the optimal rate of pile, displacement of pile top is the lowest.
Pages178
Language中文
Document Type学位论文
Identifierhttp://ir.imde.ac.cn/handle/131551/24593
Collection山地灾害与地表过程重点实验室
Affiliation中国科学院成都山地灾害与环境研究所
First Author Affilication中国科学院水利部成都山地灾害与环境研究所
Recommended Citation
GB/T 7714
陈剑. 巨型滑坡失稳特征及针对性防治技术研究[D]. 北京. 中国科学院大学,2017.
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