【作者】 王树洪；

【导师】 任旭华；

【作者基本信息】 河海大学 ， 水工结构工程， 2004， 硕士

【摘要】 近几十年来，为满足经济和社会快速发展的需要，世界上各种用途的隧洞工程的建设发展迅猛，其主要表现形式和趋势就是隧洞长度不断增大以及埋深的不断增加。大埋深将使隧洞开挖施工时遭遇到如高外水压及高压涌水、高地应力及岩爆、高地温、高瓦斯有害气体等一系列地质灾害问题，这成为制约深埋隧洞建设快速发展的主要因素。 锦屏二级水电站四条引水隧洞平均长度16.625km，最大埋深达2525m左右，洞线高程处地应力最大主应力值达54MPa，工程区属高地应力区。在前期4km长探洞施工过程中，曾发生多次较大涌水，单点最大涌水量达4.91 m~3／s，长探洞封堵后最大水压力达10.22Mpa，工程区高外水压力问题突出。如此大埋深、高外水压力、高地应力下的隧洞工程建设目前还很少有同类工程可资借鉴，这方面的研究也不多见。这就使本隧洞工程的建设面临着极大的挑战。 本文是在将围岩作为主要承载结构，支护与围岩共同作用的现代隧洞设计理论的基础上，来研究高外水压力及高地应力下隧洞围岩稳定性及支护结构安全的。首先，研究了不同渗控方案的外水压力在灌浆加固圈和衬砌上如何合理分配的问题。接着，本文在深入研究工程区高外水压力及高地应力分布规律及岩体特性的基础上，建立起高地应力、高外水压力作用下隧洞围岩结构非线性有限元仿真计算模型，然后考虑隧洞的开挖过程、水荷载的作用历史，通过计算分析得出了不同洞径、不同的灌浆圈渗透系数和不同的灌浆圈深度以及不同开挖过程与围岩及支护结构的应力、位移和塑性区的关系。计算结果表明，如果能使锦屏工程引水隧洞灌浆圈围岩具有较好的防渗性能，将高外水压力控制在灌浆圈以外，再配合透水性相对较好的支护结构以及排水措施，使灌浆圈围岩成为主要承载结构，并使衬砌结构和灌浆圈共同承载，是可以保证围岩的稳定和支护结构安全的。最后，以围岩作为主要承载结构的设计思想作为隧洞支护设计原则，进行了具体围岩加固和支护结构设计，并通过具体的长探硐封堵施工的成功实践，进一步对将围岩作为主要承载结构的设计思想作了实践验证。更多还原

【Abstract】 In the latest tens of years for meeting with the economic and social double-quick development, a great many tunnels used in a variety of fields have been built in the world. The trend of tunnel construction is more and more long-deep. In the process of construction, some special geological hazards will be met because of the great depth and long distance, such as high external waterpressure, watergushing, high geostress, rockburst, high geotemperature and nocuous gas and so on. These geological hazards become the main restricted factors of tunnel construction.The four diversion tunnels of Jinping Cascade 2 Hydroelectric Power Station is 16.625 km long averagely and 2525m deep in maximal bury-depth. In the construction region the maximum of principal geostress reached 54Mpa. The region belong to high geostress area. In the preceding excavation of 4km long exploratory tunnel, several bigger flows had taken place. The maximal flux approached 4.91m3/s and the maximal water pressure is 10.22MPa. There are few great depth, high external waterpressure and high geostress tunnels engineering and few researches on this up to present. Thus, there will be many challenges in construction of the tunnels.Based on the modern design theory of tunnels construction that the adjoining rock be regarded as primary load-bearing structure, this thesis have made researches on the stability of tunnels mother rock and the safety of support pattern under the high external waterpressure and high geostress. Firstly, the problem that external waterpressure aroused by different seepage control is how to sound distribute between the grouting rock and liner is analyzed by nonlinear computation. Secondly, grounded on the study of the distribution of the high external waterpressure and high geostress and the characteristic of the rock in engineering area, the paper built the elastoplastic FEM numerical simulation model, and think over the procedure in tunnels excavation and the history of work of water load, and then get the relations between the different tunnels diameter, different permeability coefficient and depth of the grouting rock and the deformation, stress distribution and plastic range of the surrounding rock and support structure. Finally, according to the modern design theory of tunnels construction, the particular design of country rock reinforcement and support structure are researched and presented for diversion tunnels. In addition, this paper carry out successfully the support design practice in the preceding excavation of 4km long exploratory tunnel.According to the thesis research results, the following conclusion can be drawn. If the grouting rock can possess sound anti-seepage capability and the liner structure canhold higher hydraulic permeability relatively, and if the adjoining rock can be made as primary load-bearing structure by construction measure, the stability of country rock and the safety of liner structure will be guaranteed.更多还原