酸环境干湿循环作用下泥灰岩损伤劣化分析_夏万春.pdf

书书书Journal of Engineering Geology工程地质学报10049665/2022/30(6)-2006-10夏万春，王林峰，张继旭，等 2022 酸环境干湿循环作用下泥灰岩损伤劣化分析J 工程地质学报，30(6):20062015 doi:1013544/jcnkijeg20220374Xia Wanchun，Wang Linfeng，Zhang Jixu，et al 2022 Damage and deterioration analysis of marl under dry wet cycle in acid environmentJ Journal ofEngineering Geology，30(6):20062015 doi:1013544/jcnkijeg20220374酸环境干湿循环作用下泥灰岩损伤劣化分析*夏万春王林峰张继旭冉楗杨柳钟宜宏(重庆交通大学山区公路水运交通地质减灾重庆市高校市级重点实验室，重庆 400074，中国)摘要针对库区消落带泥灰岩的最不利作用环境 酸环境干湿循环下力学性质损伤劣化问题，以岸坡泥灰岩为研究对象，分别开展 pH=3，5，7 溶液条件下的干湿循环试验，分析了酸环境干湿循环作用下泥灰岩单轴抗压强度的劣化规律，查明了其对泥灰岩力学性质的损伤劣化特性，采用颗粒流软件对比探究了不同循环次数对力学强度参数的影响规律，并结合库区消落带岩体劣化现象分析了层进劣化机理。研究结果表明:pH=3，5，7 溶液环境下泥灰岩单轴抗压强度变化均与干湿循环次数呈反比关系，累积劣化度 Sn在 34.79%54.31%之间变化，且呈现快速上升、缓慢发展、趋于平稳的变化趋势，而峰值应力劣化范围为 8.79%35.61%;泥灰岩黏聚力 C、内摩擦角、弹性模量 E 均随干湿循环次数的增加而不断降低，且损伤劣化以圈层渐进的模式进行;库区消落带岩体受到酸溶液干湿循环作用后，附近岩体会萌生大量次生裂隙，随着循环次数的推进及损伤的持续累积，裂隙逐渐贯通并向坡内层进扩展，扩展范围和速率与干湿循环次数和溶液 pH 值有关。以上分析结论与规律可为库岸山体滑坡崩塌失稳、库区危岩基座软化、蓄水渗漏等灾害的预测与应急防治提供科学依据和理论方法。关键词干湿循环;泥灰岩;三轴压缩;颗粒流;损伤劣化中图分类号:P642.3文献标识码:Adoi:1013544/jcnkijeg20220374*收稿日期:2022620;修回日期:20221205基金项目:重庆市自然科学基金项目(资助号:cstc2020jcyjmsxmX0218)This research is supported by Chongqing Natural Science Foundation(Grant Nocstc2020jcyjmsxmX0218)第一作者简介:夏万春(1997)，男，硕士生，主要从事岩土工程病害机理与控制领域的研究 E-mail:xiawanchunoutlookcom通讯作者简介:王林峰(1983)，男，博士，教授，博士生导师，主要从事地质灾害减灾理论技术领域的科研与教学工作 E-mail:wanglin-fengcqjtueducnDAMAGE AND DETEIOATION ANALYSIS OF MAL UNDE DY WETCYCLE IN ACID ENVIONMENTXIA WanchunWANG LinfengZHANG JixuAN JianYANG LiuZHONG Yihong(Key Laboratory of Mountainous Area Highway Transportation and Transportation Geological Disaster eduction in University ofChongqing，Chongqing Jiaotong University，Chongqing 400074，China)AbstractAiming at the most unfavorable environment of marl in the fluctuating zone of the reservoir areatheproblem of damage and deterioration of mechanical properties under dry-wet cycle in acid environment，taking bankmarl as the research object，the dry-wet cycle tests under the condition of pH=3，5，7 solution were carried out re-spectively，the deterioration law of uniaxial compressive strength of marl under dry-wet cycle in acid environmentwas analyzed，and the damage deterioration characteristics of marl to mechanical properties were found out The in-fluence law of different cycle times on mechanical strength parameters is explored by using particle flow software，and the mechanism of stratification deterioration is analyzed in combination with the deterioration phenomenon ofrock mass in the fluctuating zone of the reservoir area The results show that the change of uniaxial compressivestrength of marl in pH=3，5，7 solution is inversely proportional to the number of dry-wet cycles，and the cumula-tive deterioration degree Snvaries from 34.79%to 54.31%，and shows a trend of rapid increase，slow developmentand tends to be stable，while the range of peak stress deterioration is 8.79%35.61%The cohesion C，internalfriction angle and elastic modulus E of marl all decrease with the increase of the number of dry-wet cycles，andthe damage deterioration is carried out in the progressive mode of circle layer After the rock mass in the fluctuatingzone of the reservoir area is subjected to the dry-wet cycle of acid solution，a large number of secondary cracks willsprout in the nearby rocks with the advance of the number of cycles and the continuous accumulation of damage，the cracks gradually run through and expand to the inner layer of the slope The expansion range and rate are relat-ed to the number of dry-wet cycles and the pH value of the solution The above analysis conclusions and laws canprovide scientific basis and theoretical methods for the prediction and emergency prevention of disasters such as col-lapse and instability of landslide，softening of dangerous rock base and water storage leakage in the reservoir areaKey wordsDry-wet cycle;Marl;Triaxial compression;Particle flow;Damage degradation0引言三峡库区库岸边坡消落带泥灰岩常处于浸湿或干湿循环作用环境中，且随着水质的变化常被不同pH 值的水溶液反复腐蚀。这些腐蚀和循环作用将致使岩石微裂纹和孔隙等缺陷萌生、扩展及贯通，造成岩石的力学特性从宏细观方面产生不同程度的损伤和劣化，这将增加库岸山体滑坡崩塌失稳、库区危岩基座软化、蓄水渗漏等灾害发生的可能性，给三峡库区工程建设及水库运营带来诸多安全隐患。如库区段龚家方破碎岩体崩滑灾害，其由于崩滑体底部的泥灰岩具有灰岩和泥岩的双重特性，岩体结构疏松，坡体内裂隙发育，成为溶蚀液体的新通道，加剧了泥灰岩的劣化进程，造成岸坡失稳破坏(田卫明，2019)。泥灰岩本身作为一种由多种矿物胶结而成的、含有微裂纹和孔隙的碎屑类岩石材料，其岩质软弱，遇水易崩解，易风化且具弱膨胀性，工程地质特性较差，其物理力学指标受水的影响较大，一旦泡水或受化学溶液侵蚀便即刻软化。由于其弱碱性，酸性环境最可能成了泥灰岩最不利的化学环境，加之受到持续的干湿循环作用，将导致岩体劣化加剧，最终可能发育为新生地质灾害。因此库区消落带泥灰岩在酸环境干湿循环下力学性质的损伤和劣化问题有待进一步研究，可为库区工程建设提供可靠的科学依据和理论方法。针对该问题，国内外诸多学者做了大量的研究工作，并积累了丰富的成果。Yang et al(2018)认为干湿循环作用对试样岩石的影响是连续渐进的，水岩相互作用后，岩石表面的颗粒大小、特征和孔隙分布会发生显著变化。Han et al(2018)发现岩石在化学腐蚀后的峰前增量变形部分是由于达到峰值前塑性变形的增加和孔隙压缩引起的变形，且试样孔隙度随纵波速度的变化规律一致。Wang et al(2018)分析了红砂岩在酸雨干湿循环作用下的崩解特性，认为崩解过程分为早期缓慢崩解阶段、中期快速崩解阶段和后期缓慢崩解阶段 3 个阶段。黄波林等(2019)认为三峡库区岩溶岸坡消落带岩石的低劣化率夹杂结构面的高劣化率，具有不均一性。柴少波等(2022)发现随着干湿循环次数的增加，酸性干湿循环作用对节理岩石静态抗压强度的劣化最显著。申林方等(2021)发现不同 pH 溶液环境下玄武岩劣化效应在前期存在显著差异，酸性劣化程度最大，中性次之，碱性最弱，但后期劣化程度相当。Liu et al(2018)、Wu et al(2020)结合室内试验和数值模拟，建立了干湿循环作用下岩石损伤劣化颗粒流模型。诸多类似的岩石损伤劣化规律试验研究和理论分析均表明损伤劣化是一个渐进而复杂的过程(袁志辉等，2018;巩学鹏等，2019;潘振兴等，2020;安然等，2022)。根据已有的文献分析发现，酸环境下干湿循环作用对岩石的损伤劣化是一个渐进的过程，外部