水库运行期岸坡消落带红砂岩抗拉强度劣化机制

发布时间：2018-04-17 11:01

本文选题：岩石力学 + 红砂岩　；参考：《岩石力学与工程学报》2017年11期

【摘要】：红砂岩广泛分布于三峡库区,弄清岸坡消落带红砂岩的抗拉强度在水库运行期周期性"湿干"交替作用下的劣化机制,是科学进行水库运行期红砂岩岸坡稳定性分析与评价的重要前提。以三峡库区马家沟滑坡红砂岩为研究对象,自主研发能模拟水压力和"湿干"交替共同作用的岩石抗拉强度测试系统,进行消落带红砂岩在水压力和"湿干"交替共同作用下的劈裂试验;同时,基于扫描电镜(SEM)、X射线衍射(XRD)及吸水率的测试分析,探讨消落带红砂岩抗拉强度的劣化机制。试验结果表明:在水压力和"湿干"交替的共同作用下,消落带红砂岩的抗拉强度随着"湿干"交替作用次数的增加逐渐劣化,劣化幅度逐渐减小最终趋于0;在"湿干"交替作用前期,红砂岩抗拉强度的劣化幅度较大,第1次"湿干"交替作用后,劣化程度最为明显;2~4次"湿干"交替时,劣化幅度相对较大;4次"湿干"交替作用后,劣化幅度逐渐减小为0;红砂岩抗拉强度的劣化是一个不断累积的过程,是内部黏土矿物湿化过程的水化溶解与膨胀、干燥过程的失水收缩,以及水压力作用下微裂隙的增加、扩展等综合作用的结果,且黏土矿物的水化作用引起的碎屑矿物与胶结物之间的胶结变弱效应在其抗拉强度的劣化过程中起主导作用。研究成果可为合理评价红砂岩岸坡的稳定性提供科学依据。
[Abstract]:The red sandstone is widely distributed in the three Gorges reservoir area. The deterioration mechanism of the tensile strength of the red sandstone in the bank slope drop zone under the cyclic "wet dry" alternating action during the reservoir operation period is clarified.It is an important prerequisite for the stability analysis and evaluation of red sandstone bank slope in reservoir operation period.Taking the Majiagou landslide red sandstone in the three Gorges Reservoir area as the research object, a rock tensile strength test system, which can simulate the interaction of water pressure and "wet dry", has been developed independently.The splitting test of red sandstone in the drop zone under the combined action of water pressure and "wet dry" was carried out, and the deterioration mechanism of tensile strength of red sandstone in the zone was discussed based on the analysis of X-ray diffraction (XRD) and water absorption.The test results show that the tensile strength of red sandstone in the drop zone decreases gradually with the increase of the alternating action times of "wet dry" under the combined action of water pressure and "wet drying".In the early stage of "wet dry" alternation, the degradation of tensile strength of red sandstone is larger, and after the first "wet dry" alternation, the deterioration degree is most obvious when the "wet dry" alternates 4 times.The degradation range decreases gradually to zero after four "wet drying" alternations, and the degradation of tensile strength of red sandstone is a cumulative process, which is the hydration and dissolution and expansion of the internal clay mineral humidification process.The shrinkage of dehydration during drying process, and the increase and expansion of microcracks under the action of water pressure,The cementation weakening effect between clastic minerals and binders caused by hydration of clay minerals plays a leading role in the deterioration of tensile strength of clay minerals.The research results can provide a scientific basis for the rational evaluation of the stability of red sandstone bank slope.
【作者单位】：合肥工业大学土木与水利工程学院;中国电力科学研究院;
【基金】：国家自然科学基金资助项目(51579063,51379106)~~
【分类号】：TV223

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