刚度差异桩组合桩网结构路基承载特性  

Bearing Characteristics of Composite Pile-Net Structure Subgrade with Varied Pile Stiffness

作　　者：邓友生[1,2] 李文杰 张克钦 李龙 姚志刚[1,2] 肇慧玲[1] DENG Yousheng;LI Wenjie;ZHANG Keqin;LI Long;YAO Zhigang;ZHAO Huiling(School of Architecture and Civil Engineering,Xi’an University of Science and Technology,Xi’an Shaanxi 710054,China;Plie-Supported Structures Research&Test Center,Xi’an University of Science and Technology,Xi’an Shaanxi 710054,China)

机构地区：[1]西安科技大学建筑与土木工程学院,陕西西安710054 [2]西安科技大学桩承结构研究中心,陕西西安710054

出　　处：《中国铁道科学》2024年第1期26-35,共10页China Railway Science

基　　金：国家自然科学基金资助项目(51878554,41672308);陕西省自然科学基础研究计划重点项目(2018JZ5012)。

摘　　要：刚度差异桩组合桩网结构路基因具有工后沉降小、经济效益好的优点而被广泛应用于铁道工程。与传统桩承结构路基相比,该结构桩土协同工作规律更为复杂,为研究其承载特性和土体沉降变化规律,通过室内模型试验和数值计算分析刚度差异桩组合桩网结构路基在静力荷载下的桩身应力、桩土应力比、格栅应力、桩侧摩阻力和土体沉降变化特点。结果表明:刚、柔性桩的承载力主要由侧摩阻力提供;刚性桩的桩土应力比随上部荷载增加呈先增长后稳定趋势,荷载在路基中沿中心桩体向边缘桩体传递,并沿路堤行车方向朝路堤横断面方向扩散;土工格栅和碎石加筋垫层共同工作,协调荷载进行再分配,均衡路基应力分布;路基中心排桩沿横断面方向的土体沉降近似呈盆状分布,刚性桩控制路基土体变形和沉降的性状明显优于柔性桩;选择性布置刚度较大长桩可减小路基沉降量。Composite pile-net structure subgrade with varied pile stiffness has the advantages of small settlement after construction and economic benefits and is widely used in railway engineering.Compared with the traditional pile-bearing structure embankment,the pile-soil cooperative work law of this structure is more complicated.To study its bearing characteristics and variation laws of soil settlement,this study adopts the laboratory model test and numerical calculation to analyze the pile stress,pile-soil stress ratio,geogrid stress,pile side molecular resistance and soil settlement variation characteristics of composite pile-net structure subgrade with varied pile stiffness under static load.The results show that the bearing capacity of rigid and flexible piles is mainly provided by side mechanical resistance;the pile-soil stress ratio of rigid piles shows a growing and then a stabilizing trend with the increase of upper load.The load is transferred from the center pile to the edge piles along the center pile in the embankment and spreads along the embankment in the direction of traffic movement toward the embankment in the direction of the cross-section;the geogrid and the crushed stone reinforced bedding layer work together to coordinate with the redistribution of loads and to equalize the distribution of embankment stress;the soil settlement of the center pile rowing along the center pile of the embankment in the direction of cross-section is also improved.The soil settlement in the cross-section direction displays approximately a basin-shaped distribution,and the rigid piles controlling the deformation and settlement of the soil of the embankment is significantly better than the flexible piles;the selective arrangement of longer piles with larger stiffness can reduce the settlement of subgrade.

关 键 词：路基 刚度差异桩 桩网结构 承载特性 模型试验 数值计算 

分 类 号：TU473.1[建筑科学—结构工程]