论文部分内容阅读
【目的】分析水泥改良土融沉对地层位移场的影响规律,为水泥土改良冻结法应用于城市地下工程提供理论基础。【方法】以南京地铁10号线盾构出洞水平冻结加固工程为研究对象,采用三维数值模拟方法对水泥改良土融沉引起的地层位移进行了分析,采用单因素分析法,分析了融沉系数、覆土厚度、冻土壁尺寸对融沉位移场的影响规律。【结果】冻结区土体未经水泥土改良时,地表最大融沉量为12.811 cm;水泥掺入比为12%时,地表最大融沉量为1.521 cm,表明水泥的掺入可明显减小冻土融沉。【结论】水泥土融沉时,土层越深,融沉位移越大,融沉范围越小;地表融沉位移呈盆状沉降面,最大沉降位于出洞口处,随融沉系数增加,地表最大融沉量逐渐增大,但地层沉降分布规律不变;覆土厚度越大,地表融沉量越小;冻土壁尺寸增加时,地表位移发展速度变缓,地表沉降时间延长,最终融沉量增大。
【Objective】 The influence of cement-thaw thawing settlement on the displacement field of the formation is analyzed, which provides a theoretical basis for the application of the improved soil-cement freezing method in urban underground engineering. 【Method】 Based on the horizontal freezing consolidation project of the tunnel exit of Nanjing Metro Line 10, the displacement of the ground caused by the cement amelioration was analyzed by the three-dimensional numerical simulation method. By using the single factor analysis method, The Influence of Coefficient, Covering Thickness and Frozen Soil Wall Dimension on the Placing and Settlement Displacement Field. 【Result】 The maximum thawing loss of the soil in the frozen zone was 12.811 cm without cement-soil improvement. When the cement incorporation ratio was 12%, the maximum thawing settlement was 1.521 cm, indicating that the incorporation of cement could be significantly reduced Frozen soil thaw sink. 【CONCLUSION】 When the soil is thawed, the deeper the soil layer, the greater the thawing and sinking displacement, and the smaller the melting and thawing range. The displacement of the surface thaw and settlement is a basin-shaped settlement with the maximum settlement located at the exit. With the increase of the settlement coefficient, The maximum thawing settlement increased gradually, but the regularity of formation settlement did not change. The larger the thickness of soil cover, the smaller the thawing amount of surface. When the size of frozen soil wall increased, the development of surface displacement became slower and the time of surface settlement extended, Increase in volume.