摘要
小直径钢管抗滑桩作为一种新型支挡结构广泛应用于边坡加固和滑坡治理中,但其抗滑特性、受力机制及破坏模式等还有待于深入研究。结合工程背景,开展小直径钢管排桩离心模型试验,研究排桩加固边坡破坏模式、受力情况、桩间距和联系梁对其抗滑能力的影响。试验结果表明:各组模型边坡均为整体性破坏,唯独未加固边坡出现较明显的滑动面。此类结构的抗滑机制主要表现为高压注浆对地质体的改造及桩–岩土体复合结构的共同抗滑作用,其主要破坏模式为轴向受拉或受压产生的整体失稳破坏。桩间距显著影响排桩的抗滑能力,桩径比与边坡安全系数呈幂函数关系,建议此类排桩结构桩径比控制在6～12。桩后土压力基本呈现"中间大、两头小"现象,滑面以上土压力近似为三角形分布;对于有联系梁的3排桩而言,B排桩承载能力发挥随加速度增大而减小,C排桩反之。在桩顶联系梁作用下,边坡安全系数提高38.3%。
As a new retaining structure, the small-diameter steel pipe anti-sliding pile is used extensively for slope reinforcement and landslide control, but its some behaviors, such as anti-sliding characteristics, force mechanism and failure mode, etc., need to be further studied. Combining with a specific engineering, centrifugal model tests of small- diameter steel pipe row piles are used to investigate the effects of slope failure mode, stress condition, pile spacing and connection beams on slope anti-sliding capacity. The results show that the model slope in each group suffers overall structure failure, and sliding surface can be observed clearly only in slopes without reinforcement. The anti-sliding mechanism of this kind of structures represents the geological improvement by high-pressure grouting and cooperative anti-sliding activity by piles and rock-soil composite structure. The main failure mode of this kind of structure is overall instability caused by axial tension and compression. The anti-sliding capacity of row piles is affected dramatically by pile spacing. The relationship between the ratio of pile spacing to pile diameter（L/O） and factor of safety of slope is a power function, and the value of L^0 of this type of row piles is recommended to be 6 - 12. Soil pressures behind piles increase with the increasing depth first and then decrease, and they approximately present a triangular distribution above the sliding surface. For the triple-row pile structure with connection beams, the bearing capacity of pile B decreases with the increase of acceleration, while that of pile C is on the contrary. The factor of safety of slope increases by 38.3% under the action of connection beams.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2012年第A01期2644-2652,共9页
Chinese Journal of Rock Mechanics and Engineering
基金
四川交通科技计划项目(2007A15–2)
关键词
边坡工程
小直径钢管桩
排桩
离心模型试验
破坏模式
受力特性
slope engineering： small-diameter steel pipe piles
row piles
centrifugal model test
failure mode
mechanical characteristics
