交通动荷载作用下双舱综合管廊响应分析

王胜利¹，伏胜祥²，胡朋²，迟连阳^3*，涂雄伟¹，杨申朋¹，巩玉浩¹

1.济南金曰公路工程有限公司，山东 济南  250101；2.山东交通学院交通土建工程学院，山东 济南  250357；

3.新疆新工勘岩土工程勘察设计院有限公司山东分公司，山东 济南  250102

摘要：为探究车辆动荷载对粉质土地基中综合管廊（管廊）沉降与力学性能的影响，采用有限元软件PLAXIS 3D建立埋地综合管廊计算模型，采用缩尺模型试验验证数值模型的可靠性。通过施加正弦波模拟车辆动荷载，分析管廊埋深、回填土弹性模量、地下水位高度、车辆荷载幅值及加载位置等因素对管廊沉降与动力响应的影响。结果表明：1）各测点沉降均在第1秒内显著增大，而后周期性振荡并趋于稳定，有管廊底部土体沉降小于无管廊土体底部。2）管廊拉应力主要集中在左舱顶板内侧、左侧壁上部外侧和中部内侧、右侧板中部内侧，左侧壁上部外侧受到的拉应力峰值最大，左舱顶板内侧产生的波动幅度最大。3）顶板振动加速度响应较大，由顶板将振动加速度响应沿着管廊侧板和中隔墙传递至底板，顶板和侧板约在第2秒、底板约在第1秒趋于稳定，稳定后管廊顶板的振动加速度峰值最大，底板最小。4）随管廊埋深的增大，管廊底部土体沉降减小，顶板、侧板和底板的振动加速度峰值减小，推荐埋深2.5~3.0 m；随车辆动荷载幅值增大，管廊的拉应力峰值、沉降及加速度峰值均增大；车辆荷载作用于管廊正上方时对管廊最不利，拉应力与加速度峰值最大，随加载位置向左、向右偏离管廊中轴线，管廊各结构的拉应力峰值和振动加速度峰值基本减小。5）回填土弹性模量增大有助于减小管廊的沉降与加速度峰值。随地下水位高度的增大，管廊底部沉降先小幅减小后增大。

关键词：综合管廊；粉质土地基；动荷载；低塑性黏土；加速度响应

Response analysis of double-cabin comprehensive utility tunnel under traffic dynamic load effects

WANG Shengli¹, FU Shengxiang², HU Peng², CHI Lianyang^3*, TU Xiongwei¹, YANG Shenpeng¹, GONG Yuhao¹

1.Jinan Kingyue Highway Engineering Co., Ltd., Jinan 250101, China;

2.School of Civil Engineering, Shandong Jiaotong University, Jinan 250357, China；

3.Shandong Branch of Xinjiang Xingongkan Geotechnical Engineering Investigation and Design Institute Co., Ltd., Jinan 250102, China

Abstract: To investigate the effects of vehicle dynamic loads on the settlement and mechanical performance of the underground comprehensive utility tunnel in silty soil foundations, a calculation model of the buried comprehensive utility tunnel is established using the finite element software PLAXIS 3D, and a scaled model test is conducted to verify the reliability of the numerical model. By applying a sinusoidal wave to simulate vehicle dynamic loads, the influences of parameters such as tunnel burial depth, elastic modulus of backfill soil, groundwater level, vehicle load amplitude and loading position on the settlement and dynamic response of the tunnel are analyzed. The results show that: 1) The settlement at each measurement point significantly increases within the first second, followed by periodic oscillation and stabilization, with the settlement of the soil at the bottom of the tunnel being less than that without the tunnel. 2) The tensile stress in the tunnel is mainly concentrated on the inner side of the top slab of the left chamber, the upper outer side and the middle inner side of the left side wall, and the middle inner side of the right side wall, with the maximum tensile stress peak occurring on the upper outer side of the left side wall and the largest fluctuation amplitude generated on the inner side of the top slab of the left chamber. 3) The vibration acceleration response of the top slab is larger, as it transmits the vibration acceleration response along the tunnel side walls and the central diaphragm to the bottom slab, with the top slab and side walls stabilizing around the second second, and the bottom slab stabilizing around the first second; after stabilization, the peak vibration acceleration of the top slab is the largest, while that of the bottom slab is the smallest. 4) As the burial depth of the tunnel increases, the settlement of the soil at the bottom of the tunnel decreases, and the peak vibration acceleration of the top slab, side walls, and bottom slab decreases, with a recommended burial depth of 2.5 m to 3.0 m; as the vehicle load amplitude increases, the peak tensile stress, settlement, and peak acceleration of the tunnel all increase; the vehicle load applied directly above the comprehensive utility tunnel is the most detrimental to the tunnel, resulting in the maximum peak tensile stress and acceleration, while moving the loading position away from the tunnel′s central axis to the left or right generally reduces the peak tensile stress and vibration acceleration of each structure of the tunnel. 5) An increase in the elastic modulus of the backfill soil helps to reduce the settlement and peak acceleration of the tunnel. With the increase of groundwater level, the settlement at the bottom of the tunnel initially decreases slightly and then increases.

Keywords: comprehensive utility tunnel; silty soil foundation; dynamic load; low plasticity clay; acceleration response