红层水岩作用特征及库岸失稳过程分析

来源期刊:中南大学学报(自然科学版)2009年第4期

论文作者:柴 波 殷坤龙 简文星 代云霞

文章页码:1092 - 1098

关键词:红层;水岩作用;岸坡失稳;滑坡

Key words:red-bed; water-rock interaction; failure of bank slope; landslide

摘    要:为了研究三峡库区红层岩土体水岩作用特征,分析库岸失稳的过程,通过统计获得三峡库区红层滑坡的分布规律,并通过X射线衍射对矿物进行分析,结合崩解试验观察和滑带土微观结构扫描,分析红层岩石遇水崩解、软化(泥化)和膨胀的水岩作用特性。以三峡库区典型库岸为例,分析红层水岩作用引起库岸失稳的过程。研究结果表明:富含亲水膨胀性矿物是红层岩土体具有特殊水岩作用特征的关键,红层岩石崩解首先沿缺陷发生,在干湿循环过程中不仅存在失水收缩的拉破坏,还存在吸水膨胀微裂隙尖端压应力集中引起的压剪破坏;红层滑带土在遇水膨胀前、后其矿物自身无明显变化,但矿物间连接结构被破坏,孔隙数量和孔径均有所增加,致使滑带土强度极低;巴东城区北侧库岸太矶头—旧县坪段巴东组第2段(T2b2)崩滑堆积体是互层状红层岩体差异崩解所致;红层膨胀性滑带土的抗剪强度极低,以及后缘水压力的推动作用使万州区近水平地层古滑坡群形成,古滑坡前缘堆积体具有多期活动的特点。

Abstract: In order to study the water-rock interaction characteristics of red-bed rock in the Three Gorges reservoir and analyze failure process of bank slope, the distribution law of red-bed slope was obtained by statistics. According to the mineral analysis by X-ray diffraction, based on the laboratory test and scanning of microstructure, the water-rock interaction characteristics of red-bed rock was analyzed. Taking the typical bank slope in the Three Gorges reservoir as an example, the failure process of bank slope caused by water-rock interaction of red-bed rock was analyzed. The results show that hydrophilic expansibility minerals in the red-bed rock is the key of special form of water-rock interaction; the disintegration occurs along with the limitation in the rock, and in the dry-wet cycle process, not only the tension failure occurs caused by water losing shrinking, but the compression and shear failure occur, which are caused by the concentration of compressive stress in the tip of water swelling micro-fissure. The mineral in the expansibility sliding soil has no obvious change after meeting water, but the combining structure between mineral are broken. The quantity of pore and their size increase, which decreases the strength of sliding soil. It is considered that the riverside slumping mass of the second segment in Badong group in the north side from Taijitou to Jiuxianping in Badong is related with different disintegratives. The low shear strength of expansibility slide soil in red-bed and pushing effect of water pressure in the back edge results in the formation of near horizontal strata slope in Wanzhou area, whose slumping mass in the front has polyphase activities.

基金信息:国家自然科学基金资助项目
湖北省自然科学基金计划青年杰出人才项目

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