水-盐作用下红层砂岩声波特性劣化试验  

Deterioration characteristics of red-bed sandstone acoustic wave properties due to water and salt solution

作　　者：原鹏博[1,2] 杨烜宇 赵天宇 YUAN Peng-bo;YANG Xuan-yu;ZHAO Tian-yu(School of Civil Engineering and Mechanics,Lanzhou University,Lanzhou,Gansu 730000,China;Key Laboratory of Mechanics on Disaster and Environment in Western China,The Ministry of Education,Lanzhou University,Lanzhou,Gansu 730000,China;Gansu Provincial Institute of Communications Planning Survey and Design Co.,Ltd.,Lanzhou,Gansu 730030,China)

机构地区：[1]兰州大学土木工程与力学学院,兰州甘肃730000 [2]兰州大学西部灾害与环境力学教育部重点实验室,兰州甘肃730000 [3]甘肃省交通规划勘察设计院股份有限公司,兰州甘肃730030

出　　处：《岩土力学》2019年第1期227-234,共8页Rock and Soil Mechanics

基　　金：国家重点基础研究发展计划(973计划)项目(No.2014CB744701);兰州大学西部灾害与环境力学教育部重点实验室开放基金(No.201403);甘肃省交通运输厅科技项目(No.2016-02)~~

摘　　要：水-岩作用是岩石表面风化、结构破坏以及强度降低的重要原因之一,也是岩土力学研究领域的经典问题。基于此,以甘肃兰州地区红层砂岩作为研究对象,进行了10次不同(盐)溶液下的干湿循环试验,研究了红层砂岩的声波劣化特征以及劣化机制。结果表明:(1)随着干湿循环次数的增加,试样的质量逐渐减少,纵、横波速逐渐降低,这种变化在高浓度Na2SO4溶液中更为明显,且垂直层理试样比平行层理试样更容易劣化;(2)通过对岩石纵波的频谱特征分析,发现Na2SO4溶液条件下,岩石的能量损失较NaCl溶液更为显著。同种溶液,浓度越高,岩石的能量消散越大;(3)在劣化过程中,出现了2种形式破坏:端面剥蚀和沿层理的横向断裂和纵向劈裂;(4)微观结构分析表明,水-盐作用下岩石矿物颗粒的胶结变差,导致孔隙变大是影响红层砂岩声波劣化的主要原因。研究成果对于红层砂岩边坡长期稳定性评价具有较大的参考价值,同时,也为砂岩质文化遗产风化病害的评价、保护提供科学依据。Water-rock interaction is one of the most important causes of surface weathering, structure damage and strength reduction of rock. Water-rock interaction is also a classical problem of research field of rock and soil mechanics. In order to investigate the deterioration characteristics and mechanism of acoustic wave properties of red-bed sandstone in Lanzhou City, Gansu Province, a series of dry-wet cycle tests with different salt solutions is conducted. The research results show that the mass, P-wave and S-wave of red-bed sandstone specimens gradually decrease with the increasing of the number of dry-wet cycles with salt solution, especially with sulphate solution. Furthermore, it is easier for the samples perpendicular to the direction of bedding plane than the samples parallel to the direction of bedding plane to get deteriorated. Based on the P-wave spectrum analysis, the sulphate solution causes more energy loss than the sodium chloride solution. For the same salt solution, there is a highly positive correlation between the energy loss and the salt solution concentration. During the deterioration process, there are two types of deterioration, the end-face pulverization and rupture along the bedding plane. The microstructure analysis indicates that the cementation weakening of mineral particles and void increasing of rock due to the dry-wet cycles with salt solution are the main reasons of degradation of red-bed sandstone acoustic wave properties. Research results have important implications for the long-term slope stability evaluation of red-bed sandstone, and the evaluation and control of weathering disease of stone cultural heritage.

关 键 词：红层砂岩 声波特性 水-岩作用 劣化机制 

分 类 号：TU452[建筑科学—岩土工程]