水下浅埋小间距隧道型钢拱架受力性状的监测及分析

湘江大道浏阳河隧道是我国第一座用矿山法施工的水下浅埋小间距公路隧道,隧道采用台阶法开挖,初期支护大量采用全环布设的型钢拱架.隧道支护拱架的受力性状是支护体系稳定的关键控制因素之一.通过对施工现场钢拱架的应力和位移的测试,基于大量的实测数据,对拱架的受力性状开展研究.结果表明:型钢拱架在拱顶和仰拱底的应力较大；下台阶开挖...

FIELD MONITORING AND ANALYSIS OF MECHANICAL BEHAVIOR OF SECTION STEEL FRAME FOR THE SHALLOW AND SMALL SPACING UNDERWATER TUNNEL

Liuyanghe Tunnel is the first shallow,small spacing underwater road tunnel by mining method in China,bench cut method was adopted and circular section steel frame was used as one of primary support measures in construction.The loading state of the arch frame is one of the key factors to be controlled to the stability of the support system.The stress and displacement of the arch frame were measured on site,and based on the massive measured data,the mechanical behavior of section steel frame was analyzed.The research shows that the stress is larger in vault and invert bottom;the stress is changed due to lower bench excavation,pouring concrete at inverted arch and secondary lining,the local stress for section steel frame of the ahead tunnel chamber is increased because of the laggard chamber excavation;the arch frame stress change is related to time-space effect and river water permeability.The test results of stress and displacement show that the bench length is reasonable.