多排微型桩框架结构加固边坡离心模型试验研究

Centrifugal model test of slope reinforced bymulti-row micro-pile frame structure

多排微型桩框架结构是边坡治理的一种有效手段,其理论研究滞后于工程应用。为研究该结构在边坡加固中的变形、受力特征和加固机制,开展了多排微型桩框架结构加固土质边坡离心模型试验。研究表明:试验中边坡变形破坏模式为蠕滑-拉裂型推移式变形破坏,分为弹性变形、塑性变形、变形稳定3阶段;与未加固边坡相比,基于多排微型桩框架结构加固的边坡抗滑稳定性显著提高,边坡稳定性系数最高提升了156%;试验中影响边坡加固效果的因素重要性依次为锚固深度、桩数、桩间距;土压力作为滑坡向前推力,沿深度方向近似呈“上小下大”的三角形分布,作用于桩-土复合结构使桩身和框架梁弯矩曲线分别呈现反S形和反C形分布;框架横、纵梁弯矩分布受布桩方式影响显著,4排×4列的框架横、纵梁最大弯矩值相近,而4排×3列的纵梁最大弯矩值是横梁的3倍。研究成果可为该结构在工程应用上提供理论指导与设计依据。

Multi-row micro-pile frame structure is an effective means for slope treatment,and its theoretical research lags behind the engineering application.To study the deformation and stress characteristics and reinforcement mechanism of the structure in slope reinforcement,the centrifugal model test of the slope reinforced by multi-row micro-pile frame structure was carried out.The test results show that the deformation and failure mode of the slope in the test is creep-tensile thrust-type,which is divided into three stages:elastic deformation,plastic deformation and deformation stability.Compared with the unreinforced slope,the anti-slide stability of the slope reinforced by multi-row micro-pile frame structure is significantly improved,and the factor of safety for the slope is increased by 156%.The importance of the factors affecting the slope reinforcement effect in the test is the anchorage depth,the number of piles,and the pile spacing.As the forward thrust of landslide,the soil pressure approximately presents a triangle distribution of‘small in the upper part and large in the lower part’along the depth direction,acting on the pile-soil composite structure,and the bending moment curves of pile body and frame beam present the reserved‘S’and‘C’distributions,respectively.The bending moment distribution of frame transverse and longitudinal beams is significantly affected by pile arrangement.The maximum bending moments of frame transverse and longitudinal beams in 4 rows×4 columns are similar,while the maximum bending moment of longitudinal beams in 4 rows×3 columns is nearly three times that of transverse beams.The research results can provide theoretical guidance and design basis for the structure in engineering application.