超短盾构区间在富水砂卵石地层穿越河流及大桥处理施工技术

Construction Technology of Ultra-short Shield Interval Crossing River and Bridge in Water-rich Sand and Pebble Strata

以成都地铁5号线洞子口站~福宁路站区间盾构隧道工程为背景,介绍盾构隧道在下穿河流及桥梁过程中地形、地质、周边环境等制约因素,并对本工程存在的施工风险进行分析,针对性制定了盾构穿越施工技术措施。盾构通过前对河底采用钢筋混凝土抗压板并进行锚索张拉固定,桥基采用袖阀管注浆加固,靠近沙河端头采用咬合桩隔水并进行袖阀管注浆加固,盾构通过时严控掘进参数并加强渣改良以减少对周边土体扰动和损失,盾构通过后采用洞内外注浆加固的措施减小施工风险,通过以上系列措施降低了盾构施工安全风险,安全顺利地通过沙河及大桥,保证了施工工期,可为类似工程提供借鉴。

Taking the shield tunnel project of Dongzikou Station to Funinglu Station in Chengdu Metro Line 5 as the background, the authors introduces the restricting factors such as topography, geology and surrounding environment of shield tunnel in the process of crossing rivers and bridges, analyzes the construction risks existing in this project, and formulates the technical measures for shield crossing construction.Before shield passing, reinforced concrete compressive slabs are adopted for river bottom, then the anchor cables are tensioned in place, sleeve valve pipe grouting is used to reinforce the bridge foundation, moreover, the interlocking pile is adopted for isolating water and sleeve valve pipe grouting is used to reinforce the end near Shahe River.During shield tunneling, the driving parameters should be strictly controlled and slag improvement should be strengthened to reduce disturbance and loss to surrounding soil.After the shield is passed, the measures of grouting reinforcement inside and outside the tunnel are used to reduce the construction risks.The safety risks of shield construction are reduced by the combination measures of the above mentioned, and shield tunneling passes through Shahe River and the bridge safely and smoothly, thus guaranteeing the construction period.It could provide reference for similar projects.