【作者】 张鹏；

【导师】 谭忠盛；

【作者基本信息】 北京交通大学 ， 桥梁与隧道工程， 2008， 硕士

【摘要】 随着社会经济的发展,今后几十年,我国要修建数条海底隧道。要在具有恒定高水头的海底修建隧道,就不可避免的遇到:防排水方式的设置,作用在衬砌结构上水压力的确定,水荷载和土荷载共同作用的耦合场中衬砌结构的受力特征,等等一系列问题,这些问题具有极高的工程实践价值。本文以我国大陆地区第一条以钻爆法修建的海底隧道——厦门翔安海底隧道为工程背景,以模型试验为主要研究方法,同时结合理论计算、数值模拟分析等多种手段,对隧道注浆圈、衬砌背后水荷载的分布规律,应力场、滲流场及应力场和渗流场共同作用下衬砌结构的受力特征进行了研究,主要研究成果如下:(1)通过对相似理论和模型试验原理的研究,求得了应力场、渗流场、应力场和渗流场共同作用的耦合场的相似准则。求得了均质围岩中针对公路隧道防排水形式下注浆圈外表面、衬砌背后水压力的理论解析公式。以原型为背景分析了衬砌背后水压力与围岩渗透系数、注浆圈渗透系数、注浆圈厚度和隧道控制排水量各个变量之间的关系。(2)利用隧道及地下工程试验中心研发的水土共同作用模型试验台架系统、引进了光纤光栅应变测试系统,以F4全强风化囊地段的S5d隧道工程为原型,研究了渗流场中注浆圈外、衬砌背后水压力在全封堵方式下、限排方式下和逐级加大水头的过程中的分布变化规律,得到了注浆圈的水压折减作用规律。进行了隧道模型在应力场、渗流场、应力场和渗流场共同作用的耦合场中的模型试验。(3)利用水压力作用系数的概念,形象说明了注浆圈外和衬砌背后水压力的分布和变化规律。注浆圈外侧水压分布近似圆形,衬砌背后水压分布近似“葫芦”状。环向盲管的设置对结构受力有利。(4)依靠光纤光栅精确的应变数据采集,得出了衬砌结构在应力场、滲流场和耦合场中的形变特征和应力变化规律。隧道结构在应力场和渗流场共同作用的耦合场中受力最不利,其次是渗流场,最后是在应力场中的受力。隧道结构受力的最不利部位为仰拱内表面,其次是拱脚外表面,最后是拱顶内表面。水荷载是隧道结构设计的主要荷载,衬砌仰拱部位是设计的重中之重。(5)隧道衬砌结构的应力和地下水静水头近似成正比例线性关系。限排方式下,随着排水量的增大,水压力作用系数减小,隧道衬砌结构的安全系数随之增大,衬砌结构上的应力随之减小。地下水渗流改变了土体结构,渗流体积力、渗透压力施加在衬砌结构上,隧道结构土产生应力增量,因此耦合场对衬砌结构的作用要大于应力场和渗流场单独作用的叠加。(6)结合相似原理和模型试验的特点,推得返回工程原型的相似准则,原型隧道衬砌结构的应力和内力计算公式,最终得出了衬砌结构各部位在应力场、渗流场和耦合场中的安全系数。更多还原

【Abstract】 With the development of the social economy, our country will have to construct several subsea tunnels in the next several years. It is ineviTab.meeting many problems while people construct tunnels under the sea with the constant high hydraulic pressure. The high valuable problems are the setting of waterproof and drainage system, the value of the water pressure acting on the lining structure, the characteristics of the lining structure in coupled field with the interaction of water load and soil load. Considering the first subsea tunnel by drilling and blasting method in China mainland——subsea tunnel on Xiamen Xiang’an as the engineering background, using model test for the major research method, combined with other methods, such as the theoretical calculations, the numerical simulation analysis and so on, this thesis has made research on the distribution law of water pressure upon lining and outer surface of grouted ring, and the stress characteristics of lining structure in stress filed, seepage filed and coupled filed. Major research results are as follows:(1)Based on the study of the similar theory and the principles of model test, the similar criteria in stress filed, seepage filed and coupled filed, the theory analysis formula of the water pressure at outer surface of grouted ring and lining back in case of highway tunnel waterproof and drainage style are deduced. The relationship between the water pressure on lining back and the permeability coefficient of the surrounding rock, the permeability coefficient and the thickness of the grouted ring, the controlled drainage volume are analyzed in practical engineering.(2)Using the model test system researched by Tunnel &Underground Engineering Test Research Center, and the Fiber Bragg Grating Strain-testing System, as the tunnel project S5d in the strong decomposed bag F4 for the prototype, the distribution law of the water pressure at the outer surface of the grouted ring and the lining back in the process of the entire plugging, limited drainage and increasing the water load are researched. The law of water pressure reduction by grouted ring is attained. The model test in stress filed, seepage filed and coupled filed are carried out.(3)Using the concept of water pressure action coefficient, the distribution and change law of the water pressure at the outer surface of the grouted ring and the lining back were vividly illustrated. The distribution of the water pressure at the outer surface of the grouted ring approximates a circle. The distribution of the water pressure at the lining back approximates a calabash. The setting of ring blind pipe is advantageous to the structure.(4)By the precise date collected by the FBG, the deformation characteristics and the stress change law of the lining structure in stress filed, seepage filed and coupled field are attained. The runnel structure is the most disadvantageous in the coupled field, next is in the seepage field, and finally is in the stress field. The most unfavorable part of the tunnel structure is the inner surface of the invert, next is outer surface of the arch foot, and finally is in the inner surface of the vault crown. For design the tunnel structure, the water load is the main load.(5)The stress of the tunnel structure is in proportion to the groundwater static water head approximately. In the process of the limited drainage, with the increasing of the displacement, water pressure action coefficient decreases, the safety coefficient of the tunnel lining structure increases, the stress of the lining structure decreases. The groundwater seepage flow changes the structure of the soil, so the seepage body force and the seepage pressure act on the lining structure, the stress increment of the tunnel structure is produced. So for acting on the lining structure, the influence of the coupled field is more than the superposition influence of the stress field and the seepage field.(6)Combined with similar theory and the characteristics of the model test, the similar criteria of returning to engineering prototype, the formula of the stress and the internal force of the lining structure are deduced. Finally the safety factor of the lining structure in the stress field, the seepage field and the coupled field are attained.更多还原