知识与财富的链接
基于盾构进洞地基冻结法加固免拔管的需要,选取PVC塑料管作为盐水冻结管,开展了PVC管(接头)在冻结过程中的抗弯强度和挠度、拉伸剪切强度、水密耐压、温度应力试验研究,得出PVC管(接头)抗弯强度随冻结温度降低而增大,挠度随冻结温度降低而减小的结论。-30 ℃低温冻结比常温下抗弯强度平均增加了9.4%,挠度平均减小了74%;PVC管接头拉伸抗剪强度大于2.48 MPa。运用数值模拟方法,分析得出盾构进洞水平冻结加固工况下PVC冻结管最大弯曲应力、剪应力和位移值,与试验得出的PVC管强度和挠度值进行了安全度校核,现场试验也验证了PVC冻结管的水密性和可切割性。因此,PVC冻结管在盾构进洞盐水水平冻结工程中应用具有可行性。
Based on the need of freezing pipe reserved in horizontal freezing construction for shield arriving,PVC plastic pipe can be used as brine freezing pipe. Series test, such as flexural strength and bending test, tensile shear strength test, water tightness test, thermal stress test for the PVC pipe have been made. The tests’ results indicate that the flexural strength of PVC plastic pipe increases and the bending decreases with the freezing temperature declining. At the freezing temperature of 30 degree below zero, the flexural strength is up to percent 9.4 and the bending drops to percent 74, and the tensile shear strength of the PVC plastic pipe is greater than 2.48MPa. Moreover, the maximum stress in bend, shear stress and the displacement of the PVC pipe in horizontal freezing construction for shield arriving are acquired by numerical simulation analysis, and the safety factor for numerical computing datum, such as bending stress,shear shress and the displacement is checked by the flexural strength and bending test. At the same time, water tightness and cutability of PVC freezing pipe meets the demand of brine horizontal freezing with the field test in shanghai subway. Therefore, The feasibility for PVC pipe applied in Shield arriving horizontal freezing Construction was verified.
