岩体水岩循环对边坡嵌岩桩力学行为影响研究  

Study on the Effect of Rock Mass Wetting and Drying Cycle on the Mechanical Behavior of Rock-socketed Piles on Slopes

作　　者：曹廷 何刘[2] 王维 赵旺 刘钊 钟俊辉 CAO Ting;HE Liu;WANG Wei;ZHAO Wang;LIU Zhao;ZHONG Junhui(Survey and Design Corporation of Power China Chengdu Engineering Corporation Limited,Chengdu 610072,China;Faculty of Geosciences and Engineering,Southwest Jiaotong University,Chengdu 611756,China)

机构地区：[1]中国电建集团成都勘测设计研究院有限公司,四川成都610072 [2]西南交通大学地球科学与工程学院,四川成都611756

出　　处：《工程科学与技术》2025年第2期234-245,共12页Advanced Engineering Sciences

基　　金：中国电建集团成都勘测设计研究院有限公司科研项目(P39718);国家自然科学基金项目(41602293)。

摘　　要：为研究水岩循环条件下,库岸岩体强度弱化对边坡嵌岩桩力学行为影响。以两河口水库洛古大桥嵌岩桩边坡粉砂质板岩为研究对象,通过水岩循环弱化试验,分析岩石力学强度指标随着水岩循环次数的弱化规律,基于岩石微观结构及矿物成分变化特征揭示其弱化机理;通过广义Hoek-Brown准则和有限差分数值模拟,系统分析嵌岩桩在不同水岩循环次数后力学行为演化特征。研究结果表明:随着水岩循环次数的增加,岩石的单轴抗压强度、弹性模量、黏聚力、内摩擦角逐渐减小,泊松比逐渐增大,各项力学参数与循环次数之间呈现出良好的幂函数和对数相关性。岩石易水化矿物的水解消失和微观裂隙的聚集效应是导致力学指标水岩循环弱化的根本原因。水岩循环对嵌岩桩的力学行为具有显著影响,随着水岩循环次数的增加,位于同一深度的嵌岩桩桩身轴力逐渐增大,侧摩阻力逐渐减小,桩端阻力具有逐渐增大的趋势;嵌岩桩桩体总侧摩阻力随着水岩循环次数的增加有整体减小的趋势。不同循环次数后的嵌岩桩变形监测发现,随着循环次数的增加,各深度下嵌岩桩的水平位移、桩顶和桩底的沉降量都有增加的趋势。因此,在库岸边坡嵌岩桩的设计施工过程中,应充分考虑水岩循环对嵌岩桩力学性能的影响,避免因水岩循环导致嵌岩桩承载能力不足。Objective This study addresses the critical issue of mechanical property degradation in rock-socketed piles under cyclic wetting-drying conditions during reservoir operation.The research aims to quantitatively evaluate the weakening mechanisms of sandy shale and systematically reveal the evolution characteristics of pile bearing behavior under hydraulic cycling effects.Methods Cyclic wetting-drying tests were conducted on sandy shale specimens from the Luogu Bridge slope in Lianghekou reservoir.The generalized Hoek-Brown criterion was applied to characterize rock mass degradation,while finite difference numerical modeling incorporating MohrCoulomb constitutive relationships simulated pile behavior.Microstructural analysis using scanning electron microscopy(SEM)and X-ray diffraction(XRD)revealed mineralogical alterations.A computational model was established considering reservoir water level fluctuations between 2785 m(dead water level)and 2865 m(storage level),with 35 m-long rock-socketed piles(Pile 1-1 and 1-2)analyzed under 100 wetting and drying cycles.Results and Discussions The findings reveal that after 28 wetting-drying cycles,the uniaxial compressive strength,Young’s modulus,cohesion,and internal friction angle of the rock gradually decrease by 20.82%,25.97%,14.83%,and 28.67%,respectively.Simultaneously,Poisson’s ratio gradually increases,with a degree of deterioration of 44.13%.The mechanical parameters demonstrate strong correlations with the number of cycles through power and logarithmic functions.Microstructural analysis of the rocks indicates that after 28 cycles,hydration-prone minerals decrease,with mica content reducing from 35.1%to 27.5%,chlorite content from 11.4%to 8.4%,and anorthose content from 25.3%to 14.5%.Scanning electron microscope results highlight significant damage to the rock specimens’microstructure after 28 cycles,including an increase in cracks and pores and an expansion of the dissolution area.The loss of hydration-prone minerals and the accumulation of microscopic cracks a

关 键 词：库岸岩石 水岩循环 强度弱化 嵌岩桩 力学特性 

分 类 号：P642.3[天文地球—工程地质学]