【作者】 陈洪；

【导师】 李国富；

【作者基本信息】 扬州大学 ， 结构工程， 2009， 硕士

【摘要】 随着社会经济的快速发展,各种各样的隧道工程建设,如公路隧道、铁路隧道、地铁隧道、跨海隧道等,正以前所未有的速度在增加。隧道在开挖及建设过程中会破坏地层或围岩原有的结构体系,并且隧道所处地层或围岩的地质条件复杂多样,经常遇到膨胀岩土、大地压大变形、地震、动压等灾害的发生,从而使岩土发生新的变形或破坏,支护体系随之产生失稳现象,导致隧道防水结构体系的破坏甚至失效。因此,不论是刚性防水还是柔性防水,当隧道围岩产生变形时,都会随着岩体的开裂、剥落而丧失其防水作用,这就需要研究一种新型的防水材料,不仅自身具有很好的防水效果,而且能够自动补偿隧道支护结构出现的缝隙,对复杂和困难条件下的隧道防水具有重大的意义。膨润土是一种古老的天然材料,具有良好的粘结性、膨胀性、胶体分散性、悬浮性、吸附性、催化活性、触变性和阳离子交换性等性能,在冶炼铸造、钻井勘探、石油化工、纺织印染、食品保鲜等多种领域已有应用。近年来,膨润土极佳的吸水膨胀及防水防渗能力越来越被人们所重视,已经在垃圾填埋场防渗、核废料处置库和人工湖防渗等方面有较多的应用,除此之外,膨润土还可以作为一种新型的环保防水材料,工程实践表明膨润土具有施工简单、永久防水的优点。目前,膨润土在隧道防水工程中的应用还比较少,而其所具有的极佳的吸水膨胀性质使其在隧道防水中具有广泛的应用前景。目前对膨润土的防渗性能已经有较多的研究,其防渗能力也毋庸置疑,但对其膨胀补偿缝隙能力的研究则较少,本文针对膨润土的膨胀性质展开了一系列的试验研究,以此反映膨润土的膨胀补偿能力,并进行相应的软件模拟,主要工作内容如下:(1)选择我国性质较好的河南某地的钠基膨润土,并通过实验测定其基本性质指标。(2)对不同干密度的膨润土试样进行无荷载和有荷载的膨胀率试验,探讨相关规律,并建立膨胀应变与干密度,以及膨胀应变与轴向应力之间的关系式。(3)通过室内试验研究膨润土在膨胀变形受限制情况下的膨胀应力特征,建立了膨润土膨胀力与干密度之间的关系式。(4)运用同济曙光有限元正反分析软件分析膨润土作为防水材料应用于隧道的工程实例。(5)提出了防水材料的膨胀应变及支护应力的预测方法。更多还原

【Abstract】 With the rapid development of the sociol economic, a wide range of tunnel construction is increasing at an unprecedented rate, such as road tunnels, railway tunnels, subway tunnels, submarine tunnels, etc. Excavation and construction of the tunnel will destroy the original structure of the formation or rock system. And the geological conditions of the formation or rock where the tunnel is exsisted are complicated and various. The disaster of expansive rock and soil、large ground pressure and large deformation、earthquake、dynamic pressure, etc will make a new deformation or damage to the rock and soil.And the support system produces unstable phenomenon accordingly, the waterproof system of the tunnel will be damaged or even failured.So, whether it is rigid waterproof or flexible waterproof, when the rock of the tunnel produces distortions,it will lose the waterproof effect. A new type of waterproof material must be investigated. It has perfect waterproof effect, and can automatically compensate the crack of the tunnel support structure.This function has great significance to the tunnel waterproof in complex and difficult conditions.Bentonite is a very ancient natural material, it has good caking property, expansibility, colloidal dispersion, suspensibility, adsorbability, catalytic activity, thixotropy and exchangeable cations,etc. Bentonite has been used in a variety of areas such as melting and casting, drilling and exploration, petrochemical industry, textile printing and dyeing, food preservation,etc. In recent years, bentonite obtained more and more attention because of its ability of water swelling ,waterproof and anti-seepage. And it has been used in many aspects such as anti-seepage of landfill or artificial lake, nuclear waste repository,etc. In addition,it can also be used as a new type of environmental waterproof material . At present, application of bentonite in tunnel waterproofing was relatively little, but there will be extensive application prospect. Many research of the bentonite’s anti-seepage performance has been obtained, and there is no doubt that it has a ability of anti-seepage.But only a few studies of the ability of expansion and crackfills has been obtained. In this paper, systematic study on the expansibility of the bentonite has been spread, and software simulation has been carried out also. The main work is as follows:(1) Choose Na-base Bentonite with better properties of somewhere in Henan, determine the indexes of the basic properties. (2) Expansion rate test with or without load of bentonite samples with different dry density has been carried out, and the related law has been studied. The relationship between swelling strain and dry density , swelling strain and axial stress have been established.(3) The characteristics of expansion stress has been studied by laboratory test. The relationship between swelling stress and dry density has been established.(4)Forward and Backward Analysis software for 2D Geotechnical problem has been used to simulate the situations of the stress and deformation of the tunnel with bentonite waterproofing materials.(5)This paper puts forward the prediction methods of the expansion strain and supporting stress.更多还原