砂卵石地层冻结施工冻胀效应及其对既有隧道的影响分析  

Frost Heaving Effect of Freezing Method Construction in Sandy Cobble Stratum and Its Influence on Existing Tunnels

作　　者：王士民[1] 彭小雨 王亚[1] 王先明[1] 何绪虎 WANG Shi-min;PENG Xiao-yu;WANG Ya;WANG Xian-ming;HE Xu-hu(Key Laboratory of Transportation Tunnel Engineering of the Ministry of Education,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学交通隧道工程教育部重点实验室,成都610031

出　　处：《科学技术与工程》2023年第8期3446-3454,共9页Science Technology and Engineering

基　　金：国家自然科学基金重大项目(51991394)。

摘　　要：人工地层冻结法的实施会引起地层的冻胀,为了探究富水砂卵石地层冻胀特性及其对既有结构的扰动,首先阐述了土体冻胀的本质和温度与结构应力应变之间的关系,并依托洛阳轨道交通1号线塔湾站-史家湾站区间联络通道工程建立三维热力耦合数值模型,对砂卵石地层冻结期间的地层冻胀变化和既有隧道变形受力进行了数值计算分析。结果表明:冻结管降温使得冻结管周围地层中的水分冻结,土体体积膨胀,进而使联络通道设计位置上方地表出现隆起,且距联络通道中心的水平距离越近,隆起变形值就越大。地层的冻胀对既有双线隧道造成扰动,隧道结构变形主要表现为拱顶隆起、拱底下沉、靠近联络通道一侧的拱腰向隧道内侧产生横向变形,同时联络通道设计开口位置附近的管片结构出现应力集中现象。在整个冻结过程中,冻结前期设计加固区域地层的降温速率和低温扩散速率较快,地层冻胀效应变化显著,而到冻结后期受冻结范围影响地层冻胀变形和既有隧道变形的增幅均有所减小。Ground frost heaving can be caused by the implementation of freezing method.In order to explore the frost heaving effect in the water-rich and sand cobble stratum as well as its influence on the existing structure,the essence of the ground frost heaving was illustrated and the relationship between temperature and structural stress and strain was explained.And a three-dimensional coupling model was established based on the connection aisle project between Tawan station and Shiwan station of Luoyang transit line 1.changed in stratum s frost heaving effect,deformations and stress state of existing tunnels during freezing period were analyzed by numerical calculation.The results show that the cooling of the freezing pipe can freeze the water in the surrounding stratum,and the volume of soil expands,thus generating the surface uplift above the connected aisle.And the closer the horizontal distance to the center of connected aisle,the greater the uplift deformation value.The frost heaving of stratum has an influence on the existing tunnels,and there is a rise at the arch vault,a settlement at the arch bottom as well as a transverse deformation towards the inside of the tunnel at the arch haunches which is near the connected aisle.Meanwhile there is also stress concentration in the segment near the opening of connected aisle.The cooling rate and temperature diffusion rate in sand cobble stratum are relatively fast in the early period of this freezing,so the frost heaving effect of strata changes significantly.But at the later stage of freezing,growth ranges of both the frost heave deformation of the ground and the tunnel deformation decline to some extent,which is limited by the freezing scope.

关 键 词：砂卵石地层 人工地层冻结法 冻胀 既有隧道 热力耦合 

分 类 号：TU921[建筑科学—建筑设计及理论]