【作者】 阮波；

【导师】 刘宝琛； 李亮；

【作者基本信息】 中南大学 ， 道路与铁道工程， 2005， 博士

【摘要】 随着国民经济的飞速发展,铁路、公路、水利的建设速度越来越快,出现越来越多的人工边坡,人们将越来越多地遇到滑坡治理问题。预应力锚索抗滑桩作为一种实用有效的支挡工程措施已在边坡整治工程中得到了广泛地应用,然而其理论研究远远滞后于工程应用。本文以浒家洞滑坡治理工程为背景,从现场试验、理论研究及数值模拟方面上对预应力锚索桩的锚固机理及边坡稳定性分析进行研究,主要研究内容如下: (1) 对浒家洞滑坡整治工程进行安全监测设计。在施工及运营期间,对该滑坡的深部位移进行了长期的跟踪观测,研究了滑坡体及抗滑桩的变形规律,确定滑动面的位置,并对边坡稳定性进行趋势性分析。监测位移的及时反馈,为该工程信息化施工及安全运营提供了可靠保证。 (2) 根据预应力锚索锚固段应力的现场测试研究,得出软岩地层中锚固段轴力及剪应力分布特征。 (3) 采用灰色关联理论对锚索预应力锁定损失的影响因素进行了关联分析,研究结果表明,张拉荷载对锁定损失影响最大,其次是自由段长度。锚固段长度影响最小。 (4) 根据锚索预应力变化的现场长期监测结果,分析了软岩地层中锚索锁定后预应力的变化过程及其特征,并采用灰色不等时距GM(1,1)模型建立预应力锚索锁定后损失的预测模型。 (5) 建立了浒家洞滑坡开挖的三维数值分析模型,采用显式有限差分法进行了边坡开挖的三维弹塑性数值模拟,研究了边坡开挖引起的位移场、应力场的变化及开挖引起的塑性区,将模拟结果与现场实测结果进行了比较研究。 (6) 建立了预应力锚索桩的三维数值分析模型,考虑了桩、锚索及土体的耦合作用,采用显式有限差分法进行了预应力锚索桩的三维数值模拟,研究了锚索锚固段轴力分布特征及抗滑桩所受的弯矩、剪力及侧压力。 (7) 建立了浒家洞滑坡稳定性分析的三维数值分析模型,基于强度折减系数法,计算出边坡开挖前、开挖后及预应力锚索桩整治后的安全系数。更多还原

【Abstract】 With the further economic growth, the construction of railway, highway and hydroelectric in our country is undergoing rapid growth. There are many artificial slopes, and many slope remediation problems appear. The technique of stabilizing piles with prestressed anchored cables is an effective measure in landslide remediation works, which nowadays has a wide application in many fields. However, studies on theory of these structures are delayed greatly than their applications. In this thesis, mechanism and stability of stabilizing piles with prestressed anchored cables are studied by theory study, numerical simulation and field test in Xujiadong landslide. Major research work is summarized as follows:(1) Through long term deformation monitoring of the landslide, the displacement information is analyzed and feed back in time. The influence factors of landslide deformation are researched and the deformation trend is predicted. It has been proved that the observed data can correctly reflect the deformation of the landslide and meet the requirement for the timely treatment of the dangerous. It ensures the safety in construction period and normal operation.(2) Based on experimental results obtained from pull-out test, the axial load distribution as well as shear stress distribution at the interface of anchoring section is studied.(3) Based on the results obtained from the in-site experimental study, factors that contribute to instantaneous loss of load are examined, and three parameters, namely load applied by the jack to the cables, free length, and anchored length, are recognized as the main factors. Then grey-correlation theory is applied to analyze the correlation between these parameters and instantaneous loss of load. It is shown that the load applied by the jack to the cable and the free length have more influence than anchored length.(4) Monitoring of the long-term behaviour for up 3 years of six prestressed grout cables indicates two distinct phrases: phase Ⅰ, lastingabout 6-15 days, throughout which the losses of load are rapid; and phase II, which is marked by a slower and uniform rate of load loss. A method of unequal interval gray forecast GM (1,1) model is presented to solve load loss after lock-off. The study shows that theory analysis is in good agreement with experimental results.(5 ) Based on the monitoring and tests of Xujiadong landslide, a three dimensional numerical model for the landslide is established. A three-dimensional finite difference method is adopted to analyze Xujiadong landslide during and after excavation. On the basis of calculation results obtained from simulation, by means of analysis of displacement value of characteristic points in the main section and displacement vector, deformation features, stress variety and the evaluation of the global stability of the slope.(6) A three dimensional numerical model for stabilizing piles with prestressed anchored cables is established. Piles interact with rock via shear and normal coupling springs. The shear behavior of the cable-rock interface is cohesive and frictional in nature. Moment distribution, stress of normal coupling springs of piles can be received by studying the model. Axial load distribution as well as shear stress distribution at the interface of anchoring section are simulated.(7) Based on the three-dimensional elasto-plastic shear strength reduction finite difference method* slope stability in different stages is evaluated by the global safety factor.(8) Slope stability analysis is performed by limit equilibrium methods and finite difference modeling, and results of the two methods are analyzed. It is indicated that shear strength reduction finite difference method is appropriate to stability analysis of slope.(9) Monte Carlo method is used to calculate the reliability of Xiujiadong landslide. A comprehensive study is conducted to assess how uncertainty in design parameters affects the probability index values.更多还原