咬合桩围护结构在桥梁浅基加固中的应用——以陇海线坝河大桥加固工程为例  

Application of the Concentration Pile Fence Structure in the Shallow Base Reinforcement of the Bridge:Taking Longhai Line Bahe Bridge Reinforcement Project as an Example

作　　者：贺帅帅 王方旭 HE Shuaishuai;WANG Fangxu(Zhengzhou Branch of China Railway Fifth Survey and Design Institute Group Co.,Ltd.,Zhengzhou 450001,China;School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China)

机构地区：[1]中铁第五勘察设计院集团有限公司郑州分院,郑州450001 [2]兰州交通大学土木工程学院,兰州730070

出　　处：《科技和产业》2024年第3期249-254,共6页Science Technology and Industry

摘　　要：为探究咬合桩围护结构在浅基础加固中的力学特性,以陇海线坝河大桥为工程背景,选用Mohr-Coulomb本构方程,通过有限元软件MIDAS/GTS建立三维仿真模型,分析桩侧土体冲刷掏空对结构的影响,研究结构同一断面在不利工况下位移和内力的分布规律,并分析Ⅱ序桩的种类、冠梁布置、桩径对加固效果的影响。结果表明:土体冲刷后控制位移发生在桩顶长边方向且方向向内;土体冲刷掏空后土压力达到峰值且桩底弯矩为零,同时桩顶产生一定弯矩且反弯点位于桩基中部偏下;左、右侧面与迎水面背水面在受力和变形上均对称;在Ⅱ序桩为有筋桩时,其刚度对结构位移起到较大作用,无筋桩较有筋桩水平位移提高了2.75倍;冠梁作为边界约束对结构位移产生数量级影响,未冠梁较设冠梁水平位移提高43倍;咬合桩桩径与结构水平位移成反比,桩径对结构位移起到较大作用,桩径由0.8 m增加到1 m,桩径顶位移由0.18 mm增加到0.41 mm。In order to explore the mechanical properties of occlusive pile retaining structure in shallow foundation reinforcement,the Longhai Line Bahe Bridge was taken as the engineering background.The Mohr-Coulomb constitutive equation was selected,and the three-dimensional simulation model was established by the finite element software MIDAS/GTS to analyze the influence of soil erosion and hollowing out on the pile side on the structure.The distribution of displacement and internal force of the same section of the structure under unfavorable working conditions was studied.The effects ofⅡ.sequence pile types,crown beam layout,and pile diameter on the reinforcement effect were analyzed.The results show that the controlled displacement of the soil after erosion occurs in the direction of the long side of the pile top and the direction is inward.After the soil is scoured and hollowed out,the earth pressure reaches the peak and the bending moment at the bottom of the pile is zero,and a certain bending moment is generated at the top of the pile and the reverse bending point is located in the middle of the pile foundation.The left and right sides are symmetrical with the backwater surface of the frontal surface in terms of force and deformation.When the sequence pile is a reinforced pile,its stiffness plays a greater role in the structural displacement,and the horizontal displacement of the unreinforced pile is increased by 2.75 times compared with the reinforced pile,the crown beam has an order of magnitude impact on the structural displacement as a boundary constraint,and the horizontal displacement of the uncrowned beam is increased by 43 times compared with the crown beam;the pile diameter of the occlusive pile is inversely proportional to the horizontal displacement of the structure,and the pile diameter plays a greater role in the structural displacement,the pile diameter increases from 0.8 to 1.m,and the displacement of the top of the pile diameter increases from 0.18 mm to 0.41 mm.

关 键 词：咬合桩围护结构 浅基础加固 数值分析 Ⅱ序桩 冠梁 桩径 

分 类 号：TU470.3[建筑科学—结构工程]