刚性桩-半刚性桩-土工格栅增强路基承载及影响参数  

Bearing Characteristics and Influence Parameters of Rigid Pile-semi-rigid Pile-geogrid Reinforced Subgrade

作　　者：邓友生[1,2] 李文杰 冯忠居 张克钦[1,2] 李龙 姚志刚[1,2] 肇慧玲[1,2] DENG You-sheng;LI Wen-jie;FENG Zhong-ju;ZHANG Ke-qin;LI Long;YAO Zhi-gang;ZHAO Hui-ling(School of Architecture and Civil Engineering,Xi'an University of Science and Technology,Xi'an 710054,Shaanxi,China;Plie-supported Structures Research&.Test Center,Xi'an University of Science and Technology,Xi'an 710054,Shaanxi,China;School of Highway,Chang'an University,Xi'an 710064,Shaanxi,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 [3]长安大学公路学院,陕西西安710064

出　　处：《中国公路学报》2024年第2期209-218,共10页China Journal of Highway and Transport

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

摘　　要：刚性桩-半刚性桩-土工格栅是加固路基工程的一种有效方法,与传统桩网结构路基相比,桩-土相互作用更为复杂。为分析其承载特性,尤其是刚性桩桩身长度、桩径、桩间距和土工加筋材料及其种类对路基沉降和桩土应力比的影响规律,研究了复合路基加固优化设计方案,开展了在静力荷载下的室内模型试验和有限元方法理论计算。研究结果表明:刚性桩和半刚性桩的承载力均主要由侧摩阻力分担,但侧摩阻力发挥程度存在一定差异;路堤上部荷载在刚性桩-半刚性桩-土工格栅加固路基中沿中心桩体向边缘桩体传递,沿路堤行车方向向路堤横断面方向扩散;桩顶平面土体沉降在横断面上呈“W”分布,刚性桩能够显著减少其桩顶位置土体沉降量;在一定范围内,增加刚性桩的桩身长度、增大桩径、减小桩间距,能够减小7.12%~35.96%的路基土体变形和路基总沉降量,并提高路堤承载能力;在路堤中设置土工加筋材料,其与碎石垫层协同工作,可协调荷载在路基中重新分配,使其内部应力分布更为均衡;与土工格栅相比,土工格室具有三维立体结构,对减小路基内部土体沉降和调节荷载传递有更好的效果。在实际工程中,应根据上部荷载和地质条件,合理设计桩身长度、桩径和桩间距,选用合适的横向加筋体。Rigid pile-semi-rigid pile-geogrid is an effective method of reinforcing subgrade engineering.The pile-soil interaction of this method is more complicated than that of the traditional pile network structure subgrade,To analyze the bearing characteristics-especially the rigid pile length,pile diameter,pile spacing and geotechnical reinforcement materials and their influence on the settlement of the subgrade and pile-soil stress ratio-the optimization of the design of the composite subgrade reinforcement scheme was investigated under static loading.The results showed that the bearing capacity of both rigid and rigid and semi-rigid piles was mainly shared by the lateral resistance;however,there was some difference in the degree of lateral resistance.The load on the upper part of the embankment was transferred from the center pile to the edge pile in the rigid pile-semi-rigid pile-geogrid reinforced subgrade,and spread along the embankment toward the embankment cross-section.The soil settlement at the top plane of the pile shows a“W”distribution on the cross section,and the rigid pile significantly reduced the soil settlement at the top of the pile.Within a certain range,increasing the pile length,increasing the pile diameter and reducing the pile spacing of rigid piles can reduce the soil deformation of the subgrade and the total settlement of the subgrade by 7.12%-35.96%and improve the bearing capacity of the road embankment to a certain extent.Using geotechnical reinforcing materials in the road embankment,which works together with the gravel bedding,can coordinate the redistribution of the load in the subgrade,making the distribution of internal stress more balanced compared to using geogrids in the subgrade.Compared with geogrids,geocells have three-dimensional structures,which have better effect on reducing soil settlement and regulating load transfer in subgrade.The length of pile body and pile diameter and spacing should be designed reasonably,and suitable transverse reinforcement should be selected accor

关 键 词：路基工程 桩顶沉降 模型试验 土工格室 有限元分析 影响参数 

分 类 号：U473.1[机械工程—车辆工程]