摘要
粘性土渗透破坏一直受到普遍重视,但对其临界条件的理论和试验研究较少。孔隙性质(大小、分布)是影响渗透破坏的主要因素,但其具有不规则性。在理想条件下,本文将粘性土孔隙等效为均匀分布的圆管,从管道流角度分析粘性土的渗流破坏临界条件,包括临界流量、临界流速、临界水力坡降和临界渗透系数,建立了孔隙直径与临界条件的数学表达式。在理论分析基础上,设计了管道流试验装置和试验方法。选取贵州贵阳10组粘性土试样为研究对象,测出了其渗透破坏临界拖曳力,并计算分析不同孔隙直径、水温情况下的临界参数。结果表明:孔隙直径和水温对渗透破坏临界参数影响较大,在双对数图上,呈现线性关系。
The paper presents a view to research the seepage failure of cohesive soil.It often occurs in some projects,particularly the earthwork project.However,it is seldom to study the theories and tests of its critical hydraulic condition.Actually,the characters of the soil pores,including its sizes and distribution,are the main factor to influence the seepage failure.As the pore characters are irregular,it is difficult to analyze the process of seepage failure quantitatively.In the paper,the irregular pores are treated as the equally distributed pipes ideally.Thus,the process that groundwater seep into the pores is that groundwater flow into a certain diameter pipe,so the seepage failure can be analyzed by the pipe flow.The paper derives the formulas of the critical hydraulic condition based on the theories of the pipe flow,including the critical flow quantity,the flow velocity and the hydraulic gradient.For calculating the formulas,it designs an equipment and a method to test the unknown parameters.The 10 groups of cohesive soil in Guiyang city,Guizhou province,China,are selected to be tested.It obtains the average critical shear stress 32.8 Pa from the seepage under the pore diameter 1 mm.With the devired formulas,it calculates the four critical hydraulic conditions in the different pore sizes(from 1 × 10-3 to1 × 10-10 m) and the different groundwater temperature(5 ℃,15 ℃ and 25 ℃).Results show that the pore diameter and groundwater temperature influences the critical hydraulic condition of subterranean soil erosion.In the log-log plot,the pore diameter and the critical values have the linear relationship.
出处
《地下空间与工程学报》
CSCD
北大核心
2017年第6期1472-1476,1498,共6页
Chinese Journal of Underground Space and Engineering
基金
贵州省科技厅科技支撑计划社发公关领域项目(黔科合[2016]支撑2846)
南宁轨道交通集团有限责任公司产学研联合项目(YR-JJHT-2016-454)
关键词
粘性土
管道流
渗透破坏
临界条件
孔隙直径
cohesive soil
pipe flow
seepage failure
critical hydraulic condition
pore diameter