关键词: 海底隧道, CRD法, 基准控制指标, 绝对位移控制基准

Abstract:

It is an important content for construction safety in tunnel to establish the deformation criterion. The land shallow-depth-excavation area of the Xiamen subsea tunnel was constructed by CRD method, its total length is 2 525 m and which holds higher water content and lower intensity. The indices about three-dimensional absolute displacement criterion of primary support are put forward according to the distribution rules of three-dimensional displacement by non-contact three dimensional deformation monitoring with total station. In addition, three dimensional absolute displacement criterion was put forward finally by analysis of normal displacement and abnormal or dangerous displacement about eighty six measurement sections. The study results indicate that the deformation indices of tunnel construction with CRD method are vertical displacement of arch crown on CRD1, 3 and horizontal displacement of middle wall. The ultimate vertical displacement of arch crown on CRD1, 3 is 200 mm, 130 mm and the deformation of CRD3, 1 is in proportion as 0.5-1.0. The ultimate horizontal displacement of middle wall between CRD1 and CRD3 is 100 mm while it is 15mm between CRD2 and CRD4. Fifty eight abnormal and dangerous things were found by applying this criterion to ninety seven sections in scene and ensure construction safety because of adopting some measures in time.

Key words: subsea tunnel, center cross diaphragm method, criterion control indices, absolute deformation control criterion