Physico-mechanical performance of debris-flow deposits with particular reference to characterization and recognition of debris flow-related sediments  

泥石流堆积的物理力学行为

作　　者：YANG Kui XU Ze-min REN Zhe WANG Kun TANG Yong-jun TIAN Lin LUO Jun-yao GAO Hai-yan 杨愧;徐则民;任喆;王昆;唐永俊;田林;罗军尧;高海艳(Faculty of Civil Engineering and Mechanics,Kunming University of Science and Technology,Kunming 650500,China)

机构地区：[1]Faculty of Civil Engineering and Mechanics,Kunming University of Science and Technology,Kunming 650500,China

出　　处：《Journal of Central South University》2020年第9期2726-2744,共19页中南大学学报（英文版）

基　　金：Project(41931294)supported by the National Natural Science Foundation of China;Projects(U1502232,U1033601)supported by the National Natural Science Foundation of China-Yunnan Joint Fund。

摘　　要：To characterize and recognize the debris flow-related deposits,the physico-mechanical performance of four deposits from the Dongyuege(DYG),Shawa(SW),Jiangjia Gully(JJG),and Gengdi(GD)debris flows in southwest China is investigated through laboratory analyses and tests.The four debris-flow materials can all be remolded into coherent,homogeneous cylinders with high densification and strength–porosity of 25%-36%,mean pore-throat radius of 0.46-5.89μm,median pore-throat radius of 0.43-4.28μm,P-wave velocity of 800-1200 m/s,modulus of elasticity of 28-103 MPa,unconfined compressive strength(UCS)of 220-760 kPa,and cohesion of 65-281 kPa.Based on the comparison in slurryability and formability among debris-flow deposits,granular flow deposits,fluvial deposits,residual lateritic clay and loess,whether a sediment can be cast into competent cylinders for physico-mechanical tests can be regarded as a diagnostic evidence of old debris-flow deposits.The discrepancy in physico-mechanical properties among the four debris-flow deposits suggests that the combination of foregoing physico-mechanical parameters can characterize assembling characteristics of debris flow-related sediments including grain size distribution,mineralogy,and accidental detritus.Four deposited sediments above can be surprisingly classified as hard soil-soft rocks according to UCS,and the hard soil-soft rock behaviors can advance the further understanding of debris flows.为构建古泥石流堆积识别的半定量-定量标准,本文对东月各、沙瓦、蒋家沟及耿底沟四处泥石流堆积的物理力学行为进行了系统研究。实验发现,四种泥石流材料都能被重塑为最大直径和最大高度分别为100 mm和256 mm,具有块状构造的完整柱体。重塑柱体的孔隙度、平均孔喉半径、中值孔喉半径和P波波速分别为25%~36%、0.46~5.89μm、0.43~4.28μm和800~1200 m/s;弹性模量、无侧限抗压强度和内聚力分别为28~103 MPa、220~760 kPa(硬土或软岩)和65~281 kPa。通过对比颗粒流沉积物、冲积物、残积红粘土及黄土的成浆-成形能力发现,沉积物能否被重塑成可进行单轴抗压试验的柱体能被视为古泥石流堆积的判断依据。以上表征参数能够反映不同泥石流堆积在粒度组成、细碎屑矿物成分及岩屑岩石类型等方面的差异。

关 键 词：debris flow-related sediment physico-mechanical performance debris-flow susceptibility assessment of debris-flow hazard hard soil-soft rock 

分 类 号：P642.23[天文地球—工程地质学]