淤泥地层大直径盾构始发掌子面支护压力研究

Study on Support Pressure of the Initial Face of Large Diameter Shield Tunnel in Silt Stratum

为了选取合适的掌子面支护压力,保证淤泥地层大直径盾构始发的施工安全,本文以汕头市苏埃通道大直径盾构始发为背景,开展了淤泥地层大直径盾构始发掌子面支护压力的研究。通过对不同支护压力下的地表沉降和掌子面失稳破坏进行对比分析,研究结果表明:当盾构始发加固段开挖完成后,在淤泥地层掘进时,地表变形由隆起区和沉降区组成,随着支护压力的增大,隆起值逐渐增大而沉降值逐渐减小;掌子面前方土体形成斜向上的隆起区,而临近掌子面的上覆土体受到支护压力的影响较小形成沉降区;建议大直径浅覆土盾构始发的支护压力比应在1~1.2范围内。本文研究成果不仅为工程的设计施工提供依据,还可以为类似工程建设提供技术支持,因此具有十分重要的意义。

In order to select appropriate support pressure for large diameter shield tunneling in silt stra-tum and ensure the construction safety of large diameter shield tunneling, this paper studies the support pressure of large diameter shield tunneling in silt stratum under the background of large diameter shield tunneling in Sue’e Passage of Shantou City. Through the comparative anal-ysis of the surface settlement and the instability failure of the face under different support pressures, the results show that when the excavation of the initial reinforcement section of shield tunneling is completed, the surface deformation is composed of uplift zone and subsid-ence zone. With the increase of support pressure, the uplift value increases gradually and the settlement value decreases gradually;the soil in front of the metacarpal formed an upward up-lift area, while the overlying soil near the metacarpal was less affected by the support pressure and formed a settlement area. It is suggested that the support pressure ratio of large diameter shallow overburden shield should be within 1~1.2. The research results of this paper can be used for reference for similar projects.