圆梁山隧道溶洞地段抗水压衬砌结构试验分析

对圆梁山隧道溶洞地段4.5 MPa抗水压衬砌所承受的水压力及其结构应力进行现场试验,分析隧道衬砌使用型钢混凝土组合结构在高水压作用下的受力特征。衬砌壁后水压力大小是引起衬砌结构应力发展变化的显著因素,衬砌壁后水压力的分布及其变化与地表降雨补给量和泄水洞排水状况密切关联。当衬砌壁后水压力上升时,钢筋应力比混凝土应力的增长速率大,衬砌结构内缘应力比其外缘应力的增长速率大,且在衬砌壁后水压力增量较大时,结构钢筋和混凝土的应力增长速率相对较小。这表明随壁后水压力的增大,抗水压衬砌结构内型钢发挥的承载作用更明显。

Analysis on Structural Test of Lining Against Water Pressure at the Karst Section of Yuanliangshan Tunnel

Field tests on lining structure against water pressure of 4.5 MPa and its structural stress at the karst section of Yuanliangshan tunnel were carried out.And the mechanical behaviours of the composite structure of profiled bar and concrete for tunnel lining under high water pressure was analyzed.Test result shows that water pressure at the back of the lining is the prominent factor causing stress development and change in lining structure,and water pressure distribution and its change have a close relationship with surface rainfall replenishment and draining condition of drain tunnel.When water pressure at the back of the lining increases,the increasing velocity of steel bar stress is greater than that of concrete.The increasing velocity of the stress at the inner edge of the lining is greater than that at the outer edge.Stress increasing velocity of structural steel bar and concrete decreases relatively when water pressure at the back of the lining presents greater increment.It indicates that the profiled bar in lining structure against water pressure should exert more remarkable function in terms of bearing capability along with the increasing of water pressure at the back of the lining.