干湿交替条件下膨胀围岩胀缩规律的试验研究  

Test study on swell-shrink rules of swelling wall rock under dry-wet alternate conditions

作　　者：杨军平[1,2] 王沾义 周立新[1] 马勇[1] 樊永华[1] 

机构地区：[1]桂林理工大学广西岩土力学与工程重点实验室,广西桂林541004 [2]贺州市住房和城乡建设局,广西贺州542800

出　　处：《铁道科学与工程学报》2017年第1期117-125,共9页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(51368014)

摘　　要：为研究干湿交替条件下膨胀围岩的胀缩演变规律,利用南宁地区的膨胀土制作了膨胀土隧道物理模型。通过对隧道模型进行五个循环的干湿交替试验,得出了围岩在吸水及失水条件下的应力—时间关系曲线,并对围岩在吸水及失水过程中的力学响应及行为表现进行了分析与描述。结果表明:随循环次数的增加,各应力—时间关系曲线趋于平缓,各阶段围岩应力变化值呈减小及各阶段循环所耗时间呈逐渐短化的趋势。说明干湿交替作用,使围岩的胀缩能力减弱,渗透性提高。此外,在围岩湿胀引起的洞周总围岩应力增加值中,底板处最大约为40kpa,因此在隧道设计和施工时应注意底板的变形。In order to study the expansion and shrinkage evolution laws of swelling wall rock under dry-wet alternate conditions, the physic model of swelling wall rock tunnel has been made with the expansive soil in Nanning, Guangxi. After five cycles wetting-drying test of the tunnel model, the wall rock stress-time relation curves were gained under the conditions that surrounding rock water absorption and water loss, and the mechanical response and behavioral expression of the surrounding rock have been analyzed and described under the process of water absorption and water loss. The results show the change trend of each stress-time relation curves flatten out with the increase of cycling times, and the tendency of each stage of wall rock stress values becomes decrease and the time consumption of each stage gets shorter. These tendencies have demonstrated that the wetting-drying alternate action can weakens the swell-shrink ability and improves the permeability of wall rock. In addition, the total added value of surrounding rock stress which caused by wet expansion of surrounding rock around the tunnel hole, the maximum value occurs in the tunnel floor about 40kpa, so the floor deformation should be paid attention in the tunnel design and construction.

关 键 词：膨胀土隧道 胀缩演变规律 干湿循环 膨胀围岩 胀缩能力 力学响应 

分 类 号：U459.2[建筑科学—桥梁与隧道工程]