预切槽法开挖隧道地层变形及预筑拱受力试验  

Experiment on Ground Deformation During Tunneling and Pre-arch Stress by Pre-cutting Method

作　　者：王秀英 王滕[1] 李孔明[1] 贺美德[1,2] 罗平[1] WANG Xiu-ying WANG Teng LI Kong-ming HE Mei-de LUO Ping(Key Laboratory for Urban Underground Engineering of the Education Ministry, Beijing Jiaotong University, Beijing 100044, China Beijing Municipal Engineering Research Institute, Beijing 100082, China)

机构地区：[1]北京交通大学隧道及地下工程教育部工程研究中心,北京100044 [2]北京市政工程研究院,北京100082

出　　处：《中国公路学报》2017年第7期101-109,共9页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(51178026);北京交通大学研究生创新基金项目(2016YJS092)

摘　　要：为了明确预切槽法开挖隧道过程地层和预筑拱的力学响应,设计了1∶10大比尺三维地质力学模型试验,真实地模拟了预切槽法的切槽灌注和掌子面土体开挖过程,研究了预切槽法施工过程中地层变形及预筑拱结构受力情况。通过土体中埋设的位移、土压力及应变测点得到了洞周土压力和预筑拱的应变值,通过对试验数据的分析和与数值模型计算的对比,进一步了解地层变形的发展过程,寻找结构受力特征及施工过程的关键问题。研究结果表明:切槽混凝土灌注压力和灌注及时性对预筑拱成拱效果的影响较大;切槽及灌注混凝土过程引起的地层沉降占比较大,预筑拱形成后下部土体开挖引起的地层沉降较小,说明预筑拱可以保护掌子面超前核心土,显著减少隧道收敛变形,有效控制地层沉降;预筑拱两侧边墙和拱腰受压,拱顶主要受拉,采用素混凝土灌注的预筑拱极易发生破坏,实际工程设计施工时需要注意提高预筑拱抗拉性能。To clarify the mechanic response of ground and pre-arch by pre-cutting method during tunneling,the 3Dgeo-mechanics model test of large scale 1∶10 was designed to factually simulate the process of the grooving,pouring concrete and the full face excavation in the light of precutting method.Ground deformation during tunneling and pre-arch stress were investigated.Earth pressure and strain of pre-arch were obtained by setting measuring points of displacement,pressure and strain in the model soil.Through analyzing the obtained data and comparing it with the result of numerical simulation,the development of the ground deformation,stress characteristics of the pre-arch and the key problems during tunneling were further investigated.The results show that the influence of pressure and timeliness of concrete pouring on the quality of pre-arch is great.Compared with pre-cutting and pouring concrete process,ground settlement during soil excavation protected by the pre-arch is much smaller.It shows that core soil of the face can be protected by the pre-arch,the convergence deformation significantly decreases,and ground settlement can be effectively controlled.The sidewall and the haunch are in compression but the arch is in tension.The pre-arch poured by plain concrete is easy to be destroyed and hencetensile properties of the pre-arch should be enhanced in projects design.

关 键 词：隧道工程 预筑拱 模型试验 预切槽法 地层变形 力学特征 

分 类 号：U455.4[建筑科学—桥梁与隧道工程]