输水隧道管片环弯矩调整系数试验与分析

由管片错缝拼装的隧道衬砌圆环中,接头部分的挠曲刚度小于与之邻接的管片的挠曲刚度,接头部分承受的弯矩不同于管片承受的弯矩.目前,考虑接头的影响主要通过弯矩调整系数ξ来实现.但是弯矩调整系数ξ还没有通用公式,一般需要通过足尺试验来确定.由于时间和成本问题,所有隧道工程都做足尺试验不现实,故工程中经常需要借鉴类似工程的经验,这必然带来很大的随意性.以上海市青草沙输水隧道工程为依托,进行输水隧道管片弯矩调整系数的足尺试验,改变作用在管片上的径向力P和轴向力F,得到了弯矩调整系数ξ和弯矩M、轴向力F、一环管片长度L的关系公式,对隧道衬砌设计有一定参考价值.

Experimental Study on Moment Adjustment Factor of Water conveyance Tunnel Segment Lining

In segmental linings with staggered joints, the bending moment near a radial joint is weaker than that in its neighbor segment because of their difference in flexural rigidity. The joint effect is mainly materialized by adjusting the ratio of bending moment near a joint to that in the segment near the joint. Since there is no general formula to calculate the moment adjustment factor till now, a full scale test will be one practical approach to determine the factor. Because it is too expensive to do a full scale test for every project, comparing with similar projects becomes another often used method for the determination of the factor, which introduces much casualness to engineering projects. In this paper, a full-scale segment joint test was carried out, changing the radial force P and axial force F on lining segments, the internal force of the structure is calculated, the relationship between adjustment factor and average moment M, axial force F, and segment length L is established, some useful conclusions are made out.