GPST工法管片接缝防水技术研究

接缝是盾构隧道渗漏水发生的主要部位,而接缝面止水是盾构隧道防水的关键。盾构隧道接头防水是通过接缝面上的接触压力将密封材料压缩而产生堵水作用,但接触面压力又受接头错位和张开量的影响。为了解决南京地铁某GPST(地面出入式盾构)工法在超浅覆土及负覆土下掘进过程中,盾构千斤顶顶推力不足、接缝止水条难以达到预定的压缩量和挤密的问题,通过试验和仿真分析的方法,得出适用于浅覆土管片接缝的低硬度、高孔洞率止水条;止水条耐水性能试验结果表明,止水条能够满足本工程管片接缝长期止水的要求。

Study on Waterproofing Joints of Segments in GPST Method

Joint is the main part where leakage occurs in shield tunnels, and the waterproofing of the joint surface is the key of the waterproofing of shield tunnels. The waterproofing of the joints of shield tunnels depends on the compression of the water sealing materials on the contact surface of the joints under the action of the contact pressure. However, the contact pressure is influenced by the dislocation and opening of the joints. Regarding GPST ( Ground Penetrated Shield Technology) applied in the construction of Nanjing Metro, the shield is boring under super shallow soil cover or even without soil cover, the thrust force of the cylinders is inadequate, which results in insufficient compression and compactness of the water sealing strips. Tests and simulations are made in order to solve the above mentioned problems and water sealing strips with low hardness and high porosity suitable for segments under shallow soil covers are developed. The waterproofing tests on the water sealing strips developed demonstrate that the water sealing strips developed can meet the long term waterproofing requirements of the segments of the mentioned project.