新型预拌流态固化土性能及回填施工工艺

Characteristics and backfill technology of new type ready-mixed fluidized solidified soil

为解决城市浅埋地下工程施工对环境影响大、安全风险高等问题,采用创新设计、理论分析、室内试验和工程示范相结合的方法,研发城市地下大空间安全施工关键技术,确保施工安全。以太原市姚村综合管廊工程为背景,研究新型预拌流态固化土的性能及配套施工工艺,设计预拌流态固化土的配合比试验,通过流态粉煤灰水泥土和固化剂试验,测试养护3、7、28 d和不同砂土质量比的试样无侧限抗压强度及固化土体的渗透率和体积收缩率,确定采用复合掺和料-激发剂掺配方式,确定矿渣水泥与固化剂的质量比为2︰1,水灰质量比为2︰1,坍落度满足工程需要的200 mm要求。工程实践证明:采用流态固化土回填已装配管节背后肥槽可满足快速、密实的设计要求,为城市地下综合管廊的快速回填提供借鉴经验。

In order to solve the problems associated with the effects of urban shallow underground engineering construction on the environment,high safety risks,etc.,a combination of design innovation,theoretical analysis,indoor testing and engineering demonstration is adopted to develop key technologies for safe construction of large urban underground spaces to ensure the construction safety.Taking the Yaocun Comprehensive Pipe Gallery Project in Taiyuan City as the case study,the performance and supporting construction technology of the new ready-mixed fluidized solidified soil were studied,and the mix ratio test of the ready-mixed fluidized solidified soil was designed.Curing agent test,the unconfined compressive strength of the samples cured for 3,7,28 d and different sand-soil mass ratios,and the permeability and volume shrinkage of the solidified soil is tested.It is determined that the composite admixture-activator is a appropriate mixed method,meanwhile the mass ratio of slag cement and curing agent is 2:1,the water-cement ratio is 2:1,and the slump meets the requirement of the project of 200 mm.Engineering practice proves that,the solidified soil backfilling the fertilizer trough behind the assembled pipe joints can meet the requirements of fast and dense design,and the results can provide a reference experience for the rapid backfilling of urban underground comprehensive pipe corridors.