地下水封洞库施工巷道支护结构稳定性分析

STABILITY ANALYSIS OF ROADWAY SUPPORT STRUCTURE FOR GROUNDWATER SEALING RESERVOIR CONSTRUCTION

以“湛江国家石油储备地下水封洞库工程”为依托,对施工巷道局部支护方案进行分析并通过有限元数值模拟计算的手段对该处支护方案进行校核得出锚杆、喷层、钢拱架与围岩共同承担开挖荷载。边墙腰部位置的锚杆应力较大,最大数值为288.705 MPa;喷层则主要承受压应力,在喷层拱座位置压应力最大,数值为–7.638 MPa,为局部的应力集中区域,其余位置的喷层压应力约为–2.546~–0.850 MPa,计算结果均在材料的设计强度范围内。洞内开挖过程中由于洞内施工致使地下水位下降,出现地表土体开裂,在表面进行固表灌浆效果较好,现场施工中针对局部变形较大情况加强拱脚支撑,增加锁拱锚杆,或加水平横撑等措施均能达到控制变形的目标。

Based on the"Zhanjiang National Petroleum Reserve Groundwater Sealing Reservoir Project",the local support plan for the construction tunnel was analyzed and verified through finite element numerical simulation calculation.It was found that the anchor rod,spray layer,steel arch,and surrounding rock jointly bear the excavation load.The anchor rod stress at the waist of the side wall is relatively high,with a maximum value of 288.705 MPa.The spray layer mainly bears compressive stress,with the maximum compressive stress at the arch position of the spray layer,with a value of–7.638 MPa,which is a local stress concentration area.The compressive stress of the spray layer at other positions is about–2.546~–0.850 MPa,which is within the design strength range of the material.During the excavation process in the tunnel,due to the construction inside the tunnel,the groundwater level decreased and the surface soil cracked.The effect of surface grouting on the surface is good.Measures such as strengthening the arch foot support,adding arch locking bolts,or adding horizontal braces can all achieve the goal of controlling deformation in response to local large deformations during on-site construction.