基于有限元的粉土区综合管廊位移研究

郭培培¹，季宏宇^2*，王胜利³，涂雄伟³，胡朋²，迟连阳⁴

1.青岛市公路事业发展中心，山东青岛266061；2.山东交通学院交通土建工程学院，山东济南250357；

3.济南金曰公路工程有限公司，山东济南250101；

4.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：为研究地下水位变化对粉土区综合管廊位移的影响，采用有限元软件PLAXIS 3D构建埋地综合管廊数值模型，为验证综合管廊数值模型的可靠性，根据相似定理建立埋地综合管廊缩尺模型，缩尺比例为1∶20；通过改变地下水位、河道水位和埋深，模拟分析综合管廊位移的变化情况。结果表明：1）缩尺模型试验验证了数值模型的渗流参数设置合理，可用于分析不同地下水位变化对综合管廊位移的影响。2）随地下水位垂直下降幅度增大，竖直方向距综合管廊越远，路表的沉降越大；地下水位垂直下降5~7 m时，综合管廊上方路表与两侧无管廊区域路表的沉降差逐渐减小；地下水位垂直下降8 m时，综合管廊上方路表的沉降明显高于两侧无管廊区域路表的沉降。随地下水位垂直上升幅度增大，水平方向距综合管廊越远，路表的位移越小，综合管廊区域的路表与两侧无管廊区域路表的最大位移差越大；综合管廊底部所处平面地基的最大位移差增大，明显大于同一地下水位高度时的路表最大位移差。3）综合管廊的竖向位移和侧向位移随河道水位变化呈周期性变化，枯水期河道水位下降，综合管廊的沉降增大，侧向位移增大，丰水期河道水位上升，综合管廊回归原位，临近河道和路表一侧的位移受河道水位升降的影响较大。4）随地下水位下降，综合管廊埋深越浅，沉降越大，浅埋管廊的位移受地下水位变化的影响较大。在综合管廊实际工程应用中，高水位地区不宜采用浅埋方式。

关键词：综合管廊；有限元分析；地下水位；河道水位；位移

Research on the displacement of a comprehensive utility tunnel in silty soil based on finite element method

GUO Peipei¹, JI Hongyu^2*, WANG Shengli³, TU Xiongwei³, HU Peng², CHI Lianyang⁴

1.Qingdao Highway Development Center, Qingdao 266061, China；

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

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

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

Abstract: To study the impact of groundwater level changes on the displacement of a comprehensive utility tunnel in loess areas, a numerical model of the buried comprehensive utility tunnel is constructed using the finite element software PLAXIS 3D. To verify the reliability of the numerical model, a scaled model of the buried comprehensive utility tunnel is established according to similarity theory, with a scale ratio of 1:20. By varying the groundwater level height, river channel water level, and burial depth, the changes in the displacement of the comprehensive utility tunnel are simulated and analyzed. The results indicate: 1) The scaled model tests can validate the reasonableness of the seepage parameters set in the numerical model, which can be used to analyze the impact of different groundwater levels on the displacement of the comprehensive utility tunnel. 2) As the vertical drop of the groundwater level increases, the further away the road surface is from the comprehensive utility tunnel in the vertical direction, the greater the settlement of the road surface; when the vertical drop of the groundwater level is 5-7 m, the settlement difference between the road surface above the comprehensive utility tunnel and that of the adjacent non-tunnel areas gradually decreases; when the vertical drop of the groundwater level is 8 m, the settlement of the road surface above the comprehensive utility tunnel is significantly higher than that of the adjacent non-tunnel areas. As the vertical rise of the groundwater level increases, the further away the road surface is from the comprehensive utility tunnel in the horizontal direction, the smaller the displacement of the road surface, and the greater the maximum displacement difference between the road surfaces in the comprehensive utility tunnel area and the adjacent non-tunnel areas; the maximum displacement difference of the plane foundation at the bottom of the comprehensive utility tunnel increases, which is significantly greater than the maximum displacement difference of the road surface at the same groundwater level height. 3) The vertical and lateral displacements of the comprehensive utility tunnel exhibit periodic changes with variations in the river channel water level; during the dry season, the river channel water level decreases, which leads to increased settlement and lateral displacement of the comprehensive utility tunnel, while during the wet season, the river channel water level rises, causing the comprehensive utility tunnel to return to its original position, with the displacement near the river channel and road surface being significantly affected by the fluctuations in the river channel water level. 4) As the groundwater level decreases, the shallower the burial depth of the comprehensive utility tunnel, the greater the settlement; the displacement of shallow-buried tunnels is significantly affected by changes in the groundwater level. In practical engineering applications of comprehensive utility tunnels, shallow burial is not advisable in high water level areas.

Keywords: comprehensive utility tunnel; finite element analysis; ground water level; riverway level; displacement