关键词: 公路隧道, 大断面矩形顶管, 微扰动施工, 小间距隧道, 变形控制

Abstract: A case study is conducted on the Songhu roadSanmen road underpass project to control the surface settlement and deformation of adjacent structures while constructing a largesection rectangular pipe jacking tunnel with shallow overburden in the urban core area. Moreover, the metro jet system(MJS) method is used to reinforce the adjacent existing box culvert structure, a new pressure selfcompensating and locking pipe joint antireaction system is designed and developed, the pipe jacking construction parameters are scientifically and rationally set, and a novel frictionreducing thixotropic slurry and injection technology are developed, realizing microdisturbance on the surrounding environment caused by the construction of a largesection rectangular pipe jacking tunnel with small spacing. The results are as follows: (1) The MJS reinforcement technology protects the existing structure crossed by the pipe jacking. (2) The antireaction of the pipe joint controls the average cumulative retreat deformation of the pipe joint within 20 mm. (3) The primary parameters during the propulsion process are regulated within a predetermined range. (4) The frictionreducing thixotropic slurry effectively fills the building gap and reduces friction. According to the fieldmeasured deformation data, the cumulative surface settlement is controlled between 〖WT5BZ〗-〖WT５《TNR》〗19.74 and 6.92 mm, the settlement of the surrounding soil around the box culvert structure above the pipe jacking is controlled between 〖WT5BZ〗-〖WT５《TNR》〗3.67 and 3.01 mm, andthe vertical displacement of the structure is controlled between 〖WT5BZ〗-〖WT５《TNR》〗4.54 and 4.26 mm, indicating a good construction effect.

Key words: highway tunnel, largesection rectangular pipe jacking, microdisturbed construction, smallspacing tunnel, deformation control