衬垫法加固地下连续墙接缝防水与力学性能试验

Experimental waterproofing and mechanical properties of liner-reinforced diaphragm wall joints

关键词:  地下连续墙  高密度聚乙烯速格垫  接缝加固  防水  力学性能

Key words:  diaphragm wall  high-density polyethylene corrosion protection liners  joint reinforcement  waterproofing  mechanical property

摘要:

地下连续墙作为截水、防渗、承重、挡水结构,在深基坑工程中应用前景广泛。为提高地下连续墙接缝开裂后的防水与力学性能,采用高密度聚乙烯速格垫对4片带有接缝加固后的墙体和2片作为对比带有接缝未加固的墙体进行四点弯曲与注水加压试验。研究高密度聚乙烯速格垫以及植筋加固前后墙体的破坏形态、变形能力、承载能力和防水性能等。试验结果表明:采用速格垫加固后的地连墙接缝,能够显著提高承载能力及防水性能,延缓墙体开裂,并提高地连墙接缝的极限变形能力；根据墙体接缝处“荷载挠度”曲线,将墙体承载力划分为初始开裂阶段、裂缝发展阶段和破坏阶段；当墙体达到裂缝发展阶段时,需要及时考虑接缝漏水问题；随着水压增大,相同荷载条件下衬垫法加固前后墙体接缝的防水性能降低。

Abstract:

Diaphragm walls, as water interception, seepage control, load bearing, and water retaining structures, have many applications in deep foundations. To improve the waterproofing and mechanical properties of diaphragm walls after joint cracking, four-point bending, and waterproofing tests were carried out using high-density polyethylene corrosion protection liners on four pieces of wall with reinforced joints and two pieces of wall to compare with unreinforced walls with joints. To study the damage pattern, deformation capacity, load-bearing capacity, and waterproofing performance of walls before and after reinforcement with high-density polyethylene corrosion protection liners and reinforcement planting. The experimental results show that the diaphragm wall joints reinforced with corrosion protection liners can significantly improve the bearing capacity and waterproofing performance, postpone the concrete cracking, and increase the ultimate deformation capacity of the diaphragm wall joints. According to the “load-deflection” curve at the joints of the wall, the bearing capacity of the wall is divided into the initial cracking stage, the crack development stage, and the damage stage. When the wall reaches the cracking stage, the joint leakage problem must be considered quickly. As the water pressure increases, the waterproofing performance of the joints before and after corrosion protection liners decreases under the same loading conditions.