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With the rapid socio-economic development, a variety of tunnel construction projects, such as road tunnels, railway tunnels, subway tunnels, cross-harbor tunnels, etc., is increasing at an unprecedented rate. Tunnel excavation and construction process will undermine the strata or rock original structural system, and strata or surrounding rock in which the tunnel complex geological conditions often encountered in the expansion geotechnical, earth pressure large deformation, earthquake, dynamic pressure and other disasters, so that the geotechnical new deformation or damage occurs, the support system the consequent instability phenomena, resulting in damage or even failure of the structural system of tunnel waterproofing. Therefore, whether rigid or flexible waterproof waterproof tunnel surrounding rock deformation will be with the rock cracking, flaking lose its waterproof, which need to study a new type of waterproof material, not only has its own good waterproof effect, but also be able to automatically compensate for tunnel support structure, the gap is of great significance to the complex and difficult conditions of tunnel waterproofing. Bentonite is an ancient natural material, have good adhesion and expansion properties, colloidal dispersion, suspension, adsorption, catalytic activity, thixotropy and cation exchange and other properties, in the smelting casting, drilling exploration PETROCHEMICAL existing applications, textile printing and dyeing, food preservation and other areas. In recent years, the water absorption of bentonite excellent expansion and water seepage capacity has been growing emphasis on more applications already in the landfill seepage, nuclear waste repository, and the artificial lake seepage addition to outside bentonite also can be used as a new type of environmentally friendly waterproof material engineering practice shows that bentonite has a simple construction, the advantages of permanent waterproof. , Bentonite tunnel waterproofing works is still relatively small, it has excellent water-swelling properties it has broad application prospects in the tunnel waterproofing. Impermeable performance of bentonite has been more research, impervious ability no doubt, but the ability of its expansion compensation gap is smaller, launched a series of test for the swelling properties of bentonite to This reflects the expansion of the bentonite ability to compensate, and the corresponding software simulation, the main tasks are as follows: (1) choose our better nature Henan sodium bentonite, and by the experimental determination of the basic nature of indicators. (2) bentonite samples of the different dry density no load and load swell test, and to explore the correlation law, and to create a relationship between the expansion strain and dry density, and an expansion strain and axial stress. (3) expansion deformation limit case by laboratory experiments bentonite swelling stress characteristics, to establish the relationship between the the bentonite swelling force dry density. (4) the use of Tongji dawn of the pros and cons analysis of finite element analysis software bentonite as a waterproof material used in tunnel engineering examples. (5) The proposed expansion of waterproof material strain prediction methods and supporting stress.
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