共查询到16条相似文献，搜索用时 296 毫秒
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为了在求解双排全长桩和后排沉埋-前排全长桩中前桩后侧坡体推力的同时也可得到其分布模式,以便更合理确定前排桩受力特征,针对双排桩加固的基岩-覆盖层式滑坡,采用斜条分法将排间滑体分割成若干斜向平行滑面的土条;对所形成的在不同深度位置的4类典型土条,根据静力平衡条件,推导了其作用于前桩受荷段后侧的推力计算公式,进而可确定出前排桩受荷段后侧坡体推力分布模式及其合力。实例分析表明,本文方法所确定的前桩后侧坡体推力呈不规则抛物线形分布,其峰值点接近于滑面;后排桩沉埋模式时前桩后侧坡体推力比后排桩全长模式时的值小8.6%～10.6%;本文方法比传递系数法的计算值偏大10.6%～13.4%,且相对更接近于FLAC3D模拟结果。 相似文献
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岚皋县柳家坡2号滑坡的推力和规模较大,单排桩或者一般的支挡结构已经无法满足抗滑力的要求。而双排抗滑桩在满足抗滑力的同时,更具有刚度大、稳定性高等特点。为了研究岚皋县柳家坡2号滑坡在治理过程中双排抗滑桩各排桩分担的滑坡推力的大小,通过对前后两排桩进行单独受力分析,推导出桩身变形推力的计算公式;通过对双排桩治理后的滑坡进行二维模拟,对滑坡的稳定性、应力与应变以及双排桩的弯矩与剪力进行深入的探究分析。研究表明,抗滑桩在滑面处及锚固段中部受到的剪力最大,且后排桩相较前排桩所承受的滑坡推力更大,这为抗滑桩的设计计算提供了参考意义。 相似文献
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闫玉平 《水文地质工程地质》2023,(3):76-84
滑坡推力的确定对于抗滑桩设计极其重要,沉埋桩作为对传统抗滑桩的优化,其受荷段推力的研究目前主要借助于模型试验和数值模拟,缺乏深入的理论分析。为了建立沉埋桩后侧受荷段及桩顶沉埋段滑坡推力计算方法,针对沉埋桩加固的基岩-覆盖层式滑坡,基于潜在越顶破坏模式,由桩顶位置将越顶滑面分为顶部、底部两段,其中,顶部滑面上水平方向合力即为沉埋段推力,可由积分求得,底部滑面上各个方向的力求解方法与此类似;在此基础上,利用刚体极限平衡理论对底部滑面与桩受荷段所围滑体进行受力分析,进而可得受荷段推力计算公式。实例分析表明：理论算法所得沉埋段与受荷段推力值与FLAC3D结果非常接近,其中,受荷段推力、沉埋段推力、设桩位置处总推力随沉埋比的增大而分别非线性减小、增大、减小;沉埋比位于0～0.67范围内时,沉埋段与受荷段推力之比由0缓慢增大到0.30～0.50,随着沉埋比增大到0.8,该比值急剧增大到1.47～2.12;一般沉埋深度下,沉埋段推力小于受荷段推力。沉埋桩推力的理论研究对于桩体内力优化、沉埋深度确定具有重要的现实意义,将有助于该桩型的进一步推广应用。 相似文献
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双排抗滑桩是加固大型滑坡的常用工程措施之一,在实际工程设计计算中的关键环节在于简单且合理地确定作用于前后排桩上的滑坡推力。将抗滑桩受荷段前侧坡体视为水平向的温克勒（Winkler）地基,基于弹性地基梁模型,并充分考虑桩体受荷段与锚固段的变形连续性,通过迭代算法确定出后排抗滑桩受荷段前侧坡体抗力,进而可对排间坡体采用传递系数法计算出前排桩桩后滑坡推力,给出了相关的理论计算公式。通过室内模型试验验证了所提方法的合理性,并针对一大型基覆式滑坡实例,具体计算出了前后排桩上的设计滑坡推力荷载。所提计算方法可为实际工程的简化设计提供参考。 相似文献
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以作用形式较为简单的双排悬臂抗滑桩(未带连梁)为模型并基于结构力学位移法得出的双排桩滑坡推力传递分配计算公式为基础,结合推力较大的红石包滑坡作为工程实例,分别分析了双排桩静排距,前后排桩的截面尺寸和桩间土弹性模量对推力传递分配的影响,得出了以下结论:(1)当增大后排桩的刚度或减小前排桩的刚度时,桩土相互挤压作用越小, A2/A1随之减小,反之A2/A1增大。(2)增大排距b时,A1减小,A2在b=3~10m时逐渐减小,但是变化幅度不大; 在b=10~21m时,不断增大。(3)当增大桩间土弹性模量时,A2增大。(4)随着前排桩截面高度的增大,A1、A2逐渐增大; 随着后排桩截面高度的增大,A1、A2逐渐减小。 相似文献
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《岩土力学》2021,(2)
为了探讨高压注浆钢花管微型桩在真实受力状态下的抗滑特性,开展了高压注浆钢花管微型单桩和群桩加固滑坡的足尺模型试验,以及重力注浆微型单桩加固滑坡的对比试验。结果表明:高压注浆能够劈裂桩周土体,在滑动带形成树根状的胶结体,显著地改善滑坡土体的力学性能,增强桩体抵抗变形的能力,减小桩体的弯曲变形,致使滑动带土体抗剪强度增加了152.5%;较重力注浆微型桩,高压注浆钢花管微型单、群桩加固滑坡的水平极限荷载分别提高了37.8%、71.2%;极限状态条件下,高压注浆钢花管群桩中后排桩承受的水平推力和弯矩最大,前排桩次之,中间桩最小,从坡体后缘向前缘弯矩最大位置处桩身混凝土由挤压破坏转变为张拉破坏。 相似文献
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大型滑坡多排、埋入式抗滑桩设计中,需要明确桩排间距、桩顶埋深不同时各排桩分担的滑坡推力的大小及桩身推力分布形式。采用室内模型试验方法,研究滑面形态为折线形、后陡前缓的折线型滑坡在滑面位置已知情况下各排抗滑桩分担的滑坡推力,并总结出折线型滑坡在桩排间距不同时各排桩分担滑坡推力的规律。同时采用有限元强度折减法对桩顶埋深改变时（前排桩不变）桩身推力分布形式的一般规律进行了分析,提出折线型滑坡桩排间距、桩顶埋深的变化能有效改善前、后排桩分担滑坡推力的比例。研究结论对于更加安全、经济地进行多排、埋入式抗滑桩加固大型滑坡的设计具有一定指导意义。 相似文献
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《岩土力学》2020,(2)
为了探讨高压注浆钢花管微型桩在真实受力状态下的抗滑特性,开展了高压注浆钢花管微型单桩和群桩加固滑坡的足尺模型试验,以及重力注浆微型单桩加固滑坡的对比试验。结果表明:高压注浆能够劈裂桩周土体,在滑动带形成树根状的胶结体,显著地改善滑坡土体的力学性能,增强桩体抵抗变形的能力,减小桩体的弯曲变形,致使滑动带土体抗剪强度增加了152.6%;较重力注浆微型桩,高压注浆钢花管微型单桩、群桩加固滑坡的水平极限荷载分别提高了37.8%、71.2%;极限状态条件下,高压注浆钢花管群桩中后排桩承受的水平推力和弯矩最大,前排桩次之,中间桩最小,从坡体后缘向前缘弯矩最大位置处桩身混凝土由挤压破坏转变为张拉破坏。 相似文献
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为研究钢管抗滑短桩加固滑坡体的受力特性,在中国地质调查局地质灾害防治技术中心完成了4组不同桩长的钢管抗滑短桩加固碎石土滑坡的室内物理模型试验。测试堆载施加的滑坡推力作用下桩后、前土压力和桩身应变,观察滑体前缘变形破坏形态,分析滑坡推力、桩前土体抗力和桩身弯矩的分布规律试验。结果表明,滑坡推力的分布和桩前土体抗力和桩身弯矩是“S”型分布,确定了抗滑短桩的危险截面。对比分析桩长变化钢管抗滑短桩的受力特性,初步拟定钢管短桩能发挥抗滑效果的桩长下限值,即钢管抗滑短桩位于滑体中的长度应不小于滑体厚度的2/3。 相似文献
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Yongjiang Shen Yang Yu Fei Ma Feilong Mi Zhengliang Xiang 《Environmental Earth Sciences》2017,76(16):586
Double-row stabilizing piles provide larger stabilizing force and lateral stiffness than the single ones. However, the loading shared by the front and rear pile is not the same with each other because of the shadow effects. A double-row long-short stabilizing pile system is verified in this paper. Physical model tests are used to investigate the influence of short rear pile on the earth pressures evolution in the stabilized soil. Numerical models are established and calibrated with the applied displacement–force curve and monitored earth pressure in the physical model test. The influence of the short rear stabilizing pile on the soil–pile interaction is further investigated based on the numerical model. The soil–pile relative displacement, total stabilizing force and bearing proportion of front and rear stabilizing pile are used to evaluate the soil–pile interaction. It is concluded that the total stabilizing force and bearing proportion of front and rear stabilizing pile are not significantly influence by the short rear stabilizing pile when the double-row piles are arranged in a line. When the double-row piles are arranged in a zigzag form, the total resistance provided by the double-row stabilizing piles decreases as the short rear piles are being used. 相似文献
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Embedded stabilizing piles are a significant optimization measure for traditional piles used to reinforce slopes or landslides. The determination of the embedded depth of the pile top is essential for engineering design. On the basis of the potential overtop-sliding failure mechanism for a piled slope, the corresponding overall slip surface is assumed to consist of the upper part from the original slip surface of the landslide, and the lower part occurs in the local slide mass upslope of the piles. The imbalanced thrust force method is used to determine the thrust force of the upper slide mass, and a variational calculus method within the framework of limit equilibrium for the lower slide mass is provided to calculate its limit resistance. According to the equilibrium relationship between the thrust force and the limit resistance under a design factor of safety of the piled slope, a closed-form solution to the piled-slope stability is specifically derived. It can quantitatively exhibit the influences of some important factors, including the embedded depth on the factor of safety and the corresponding slip surface of the slope. The analysis results of some practical examples show that the factor of safety decreases nonlinearly as the embedded depth increases. The proposed method can be applied in practical engineering. 相似文献
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双排桩支护结构的变形与内力计算是其设计计算的重要内容之一。双排支护桩结构是由前排桩、后排桩及桩顶连系梁组成的空间门架式结构。在承受水平荷载时,后排桩向坑内发生挠曲变形,挤压桩间土体,同时桩间土体又对前排桩产生推力,使得前排桩向坑内发生挠曲变形,挤压前排桩桩前土体,以致该支护结构在传递水平荷载时,前后排桩及桩间土体之间存在非常复杂的相互作用。本文基于上述双排桩支护结构受力变形特性,将前、后排桩均视为竖向放置的弹性地基梁,以欧拉伯努利双层梁理论考虑前后排桩的相互作用,以水平向弹簧模拟桩间土相互作用,以朗肯土压力计算作用于后排桩的主动土压力,以弹性抗力法计算作用于前排桩基坑底面以下的被动土压力,以基坑底面为界人为将前、后排桩分为上下部分,并通过桩身各段的受力平衡建立前后排桩的挠曲变形控制微分方程,然后通过桩端约束及基坑坑底平面处的连续条件得到方程的解析解,给出了一种考虑桩桩相互作用以及桩土相互作用的双排桩支护结构计算方法。最后结合两个实例,将本文方法计算结果与实例结果进行对比分析,验证本文方法的可行性,以期为双排桩支护结构在工程中的设计计算提供借鉴。 相似文献
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Field monitoring and deformation characteristics of a landslide with piles in the Three Gorges Reservoir area 总被引：1，自引：0，他引：1
Landslides often occur within the reservoir area behind dams. In China, a common strategy for stabilizing these landslides is to install large piles through the landslide and into the stable ground below. The piles interact with the landslide and constitute a landslide-stabilizing pile system. The deformation of this system under the reservoir operation is more complicated than the deformation of the landslide itself. Understanding the behaviour of this system is very important to the long-term safety of landslides stabilized with piles in reservoirs. The Majiagou landslide, which was selected as a case study, was triggered by the first impoundment of the reservoir behind the Three Gorges dam. A row of anti-slide piles was installed in the landslide in 2007, but monitoring results found these were ineffective at stabilizing the landslide. Subsequently, in 2011, two longer test piles and an integrated monitoring system were installed in the landslide to better understand the failure mode of the landslide and to measure the deformation characteristics of the landslide-stabilizing pile system. Monitoring results show that the Majiagou landslide is a translational landslide with three slip surfaces. The test piles provided local resistance and partially slowed down the sliding mass behind the piles, and the landslide deformation response to external factors decreased for a time. However, after 2 years, the deformation of the landslide-stabilizing pile system reverted to seasonal stepwise cumulative displacements influenced by cycles of reservoir drawdown and rainfall. The monitoring results provide fundamental data for evaluating the long-term performance of anti-slide piles and for assessing long-term stability of the stabilized landslide under the reservoir operation. 相似文献