摘要
结合一个具体的工程算例,对一种防护网与液氮冻土墙复合基坑的支护结构进行了温度场、位移场和应力场的数值分析,比较了低温盐水冻结和液氮冻结两种情况下温度场演变规律的差异,同时判断了该新型支护结构的安全性,主要得出:液氮冻结形成所需冻土帷幕的时间要比盐水冻结早许多;液氮冻结的冻结效果优于盐水冻结,所形成的冻土帷幕强度比盐水冻结大;计算出来的位移场值均很小;其主应力最小值也都很小,最大值为0.92 MPa;最大剪应力为0.17 Mpa;计算得出拉、压、剪应力值的安全系数均远大于2.由此最终得出的结论为:该工法安全可靠,可为今后类似工程提供重要的参考依据.
In the report, a specific engineering was used as an example to perform the numerical analysis of temperature field, displacement field and stress field of a protective net and liquid nitrogen frozen soil composite foundation pit support structure, the two conditions of low temperature brine freezing and liquid nitrogen freezing were compared, and the difference of temperature field evolution law and the safety of the new supporting structure were also judged. The results indicated that the frozen soil curtain required for liquid nitrogen freezing formation is much earlier than brine freezing;the freezing effects of liquid nitrogen freezing are better than that of salt water, the frozen soil curtain is stronger than the brine;the calculated displacement field values are small;the maximum and minimum principal stresses are also small, the maximum value was 0.92 MPa, the maximum shear stress was 0.17 Mpa;The safety factors of the tensile, compressive and shear stress values are much greater than 2, which shows that the safety reserve can be guaranteed. The method is safe and reliable, and can provide an important reference for similar projects in the future.
作者
胡俊
张皖湘
汪磊
刘文博
王志鑫
Hu Jun;Zhang Xiaoxiang;Wang Lei;Liu Wenbo;Wang Zhixin(College of Civil Engineering and Architecture,Hainan University,Haikou 570228,China;China Railway Times Architectural Design Institute Co.,Ltd.,Wuhu 241001,China;Hainan Hydrogeology and Engineering Geological Survey,Haikou 570206,China)
出处
《海南大学学报(自然科学版)》
CAS
2019年第4期359-367,共9页
Natural Science Journal of Hainan University
基金
“南海系列”育才计划项目(琼人才办通[2019]21号)
海南省自然科学基金(519QN333,518QN307,518MS122)
安徽省博士后研究人员科研活动经费资助项目(2018B269)
关键词
基坑支护
液氮冻土墙
垂直冻结
围护结构
冻结壁
foundation pit support
liquid nitrogen frozen soil wall
vertical freezing
envelope structure
frozen wall