摘要
红黏土广泛分布于中国南方,其高孔隙比(>1.0)、高含水率(>35%)及裂隙发育特性易诱发边坡失稳等地质灾害。剪切波速(V_(s))作为无损检测参数,可高效表征土体物理力学状态,但现有土体物理模型多适用于常规土类,针对红黏土的研究尚存空白。本文通过三轴弯曲元系统开展固结排水试验,分析不同围压、干密度、孔隙比及埋深条件下饱和红黏土的V_(s)演化规律,确定V_(s)与有效应力(σ')、抗剪强度(τf)的统计关系,并构建红黏土力学特性评价模型。研究成果包括:(1)红黏土波速响应机制。饱和红黏土剪切波速随干密度、围压、埋深、有效应力及抗剪强度增大逐渐增加,且剪切波速与有效应力、抗剪强度呈正幂函数关系(V_(s)∝σ'^(0.32~0.45),R^(2)=0.87~0.92),而剪切波速随孔隙比增大逐渐减小。(2)红黏土双参数原位评价模型。考虑埋深(H)、剪切波速(V_(s)),分别建立饱和红黏土有效应力评价模型(σ'd=cln[(V_(s)-a)/(bexp(-H/d))])及抗剪强度评价模型(τd=f+gexp[((H-h)/i)^(2)+((V_(s)-j)/k)^(2)]),该模型能快速简便地进行有效应力与抗剪强度计算,拟合精度较高(R^(2)>0.92),能够有效揭示固结排水条件下饱和红黏土应力状态与强度变化规律。研究成果可填补高含水率红黏土(含水率w>35%)波速-力学耦合模型空白,为红黏土型滑坡滑动带土体剪切特性无损评价及其监测预警提供参考。
Laterite,widely distributed in southern China,characterized by high porosity ratio(>1.0),high moisture content(>35%),and fissure development,which frequently induces geohazards such as slope instability.Shear wave velocity(V_(s)),as a non-destructive testing parameter,can efficiently characterize soil physicomechanical states;however,existing soil physical models are primarily tailored for conventional soil types,leaving a research gap for lateritic soil.In this study it conducted consolidated-drained(CD)triaxial tests using a triaxial bender element system to analyze V_(s) development of saturated lateritic soil under varying confining pressures,soil dry densities,void ratios,and burial depths.Statistical relationships between V_(s) and effective stress(σ'),as well as shear strength(τf),were established to construct a mechanical property evaluation model for lateritic soil.Key findings include as below.(1)Wave velocity response mechanism:V_(s) of saturated lateritic soil exhibited a positive correlation with dry density,confining pressure,burial depth,effective stress,and shear strength,following a power function relationship withσ'(V_(s)∝σ'^(0.32~0.45),R^(2)=0.87~0.92).Conversely,V_(s) decreased with increasing void ratio.(2)Dual-parameter in-situ evaluation model:Integrating burial depth(H)and shear wave velocity(V_(s)),the established models for effective stress(σ'd=cln[(V_(s)-a)/(bexp(-H/d))])and shear strength(τd=f+gexp[((H-h)/i)^(2)+((V_(s)-j)/k)^(2)])separately enable rapid and accurate calculations ofσ'andτf with high fitting accuracy(R^(2)>0.92),revealing stress-state and strength variations in saturated lateritic soil under CD conditions.This research fills the gap in V_(s)-mechanics coupling models for high-water-content laterite(w>35%)and provides pivotal references for non-destructive assessment of shear properties in landslide shear zones and early warning systems.
作者
黄世传
徐兴倩
李丞
赵熹
杨苑君
王海军
HUANG Shizhuan;XU Xingqian;LI Cheng;ZHAO Xi;YANG Yuanjun;WANG Haijun(College of Water Resources,Yunnan Agricultural University,Kunming 650201,China;International College,Yunnan Agricultural University,Kunming 650201,China;School of Architectural Engineering,Kaili University,Kaili 556011,Guizhou,China;Institute of Mountain Hazards and Environment,Chinese Academy of Sciences&Ministry of Water Resources,Chengdu 610213,China)
出处
《山地学报》
北大核心
2025年第4期610-620,共11页
Mountain Research
基金
国家自然科学基金(42367025, 42307269)
云南省基础研究计划农业联合专项(202301BD070001-171)。
关键词
红黏土
剪切波速
三轴固结排水试验
力学模型
lateritic soil
shear wave velocity
consolidated-drained triaxial test
mechanical model
