杭州地铁冻结工程冻土力学特性试验研究

为保证冻结工程及隧道施工的顺利进行,以杭州地铁1号线滨江站至富春路站区间盾构过江隧道联络通道为例,对冻土体无侧限抗压、抗弯强度以及破坏挠度等进行试验研究。根据试验数据分析并结合理论计算可得到以下结论:在-10℃下各土层无侧限抗压强度为2.9～5.9 MPa,强度得到大幅度提高;破坏应变以及破坏挠度满足施工要求;相比之下冻结粉砂的抗压强度最大,淤泥质粉质黏土破坏应变较其他层土大;圆砾和粉砂的抗弯强度增幅明显,达到8 MPa以上,淤泥质粉质黏土和粉质黏土的冻土抗弯强度可以增强到4.0～5.5 MPa;淤泥质粉质黏土、粉质黏土和粉砂的破坏挠度相当,冻结圆砾土的挠度最小。

Study on Mechanical Behavior of Frozen Soil: Case Study on Hangzhou Metro

Unconfined compressive strength,bending strength and failure deflection of frozen soil is studied to ensure the safe execution of freezing and tunneling,with the construction of the connection gallery of the river-crossing shield-bored tunnel between Binjiang Road Station and Fuchun Road Station on Hangzhou Metro Line 1 as an example.Conclusions drawn are as follows： 1） The unconfined compressive strength of soil layers increase much at-10 ℃,reaching 2.9～5.9 MPa;2） The failure strain and the failure deflection meet the construction requirements;3） Compared to other soils,frozen silty sand has the highest compressive strength,and muddy and silty clay has higher failure strain than other soils;4） The bending strength of pebble and silty sand increases obviously,reaching more than 8 MPa,and the bending strength of frozen muddy and silty clay and silty clay can reach 4.0～5.5 MPa;5） The failure deflection of muddy and silty clay,silty clay and silty sand are almost the same,and the failure deflection of frozen pebble is the lowest.