南水北调穿黄隧洞衬砌土压力离心试验研究

南水北调工程穿越黄河砂土地基的输水隧洞，拟采用盾构法施工．本文进行了两类离心模型试验，一类模拟隧洞开挖，一类模拟土—结构相互作用，对穿黄隧洞的开挖稳定问题和土—结构相互作用问题进行了初步的研究．试验结果表明：由于强烈的拱效应作用，隧洞周围的砂土能够在远小于原位土压力的支护压力下保持稳定；当隧洞衬砌与周围上体有一个初始间隙（盾尾间隙）时，土作经过位移和与结构发生相互作用，最后作用在衬砌结构上的土压力远小于原位土压力．

A Study of Earth Pressure on a Tunnel Under YellowRiver by Centrifuge Testing

The underground tunnel, crossing the Yellow River for the Project of South Water Transfer to North in China, is to be built beneath 20m depth of sand soil by shield tunneling method, Two types of cen-trifugal tests were performed to investigate the excavation stability problem and the soil-structurc interaction problem respectively. Following conclusions are obtained from the test results: through arching effect, the sandy soil around the tunnel can maintain stability under small supporting pressure; the earth pressure acting on the tunnel is much less than overburden pressure if there is an initial tail void.