满流条件下管道破损诱发渗流侵蚀的试验研究  

Experimental study of seepage erosion induced by pipeline damage under full pipe flow condition

作　　者：刘成禹[1,2] 陈博文 罗洪林 阮家椿 LIU Cheng-yu;CHEN Bo-wen;LUO Hong-lin;RUAN Jia-chun(College of Environment and Resources,Fuzhou University,Fuzhou,Fujian 350116,China;Fujian Provincial Universities Engineering Research Center of Geological Engineering,Fuzhou,Fujian 350116,China)

机构地区：[1]福州大学环境与资源学院,福建福州350116 [2]地质工程福建省高校工程研究中心,福建福州350116

出　　处：《岩土力学》2020年第1期1-10,共10页Rock and Soil Mechanics

基　　金：国家自然科学基金项目（No.41272300）~~

摘　　要：针对富水砂层中地下管道破损诱发地面沉降的问题,设计了一套可视化试验装置,对骨架粒径d90=1.45~8.45mm的11种砂土样、5种满流流速下土体渗流侵蚀诱发地表沉降的规律进行了研究。研究表明:(1)管道破损诱发的土体渗流侵蚀有3种模式,分别为:只突水无沉降、形成土拱并发生沉降和溃砂沉降;(2)土体骨架粒径、破损口尺寸、厚跨比是决定土体产生何种渗流侵蚀模式的主要因素,满流流速主要影响土体沉降范围;(3)管道破损口上方土体形成土拱或溃砂时,土体骨架粒径d90与厚跨比r的关系为:当8.0≥r≥4.2时,d90随r的增大呈抛物线下降;当12.5≥r≥8.0时,d90保持不变;(4)管道破损口上方土体形成土拱或溃砂时,流速为0的初始沉降半径、沉降深度由破损口直径D与土体平均粒径d50的比值(D/d50)决定;沉降半径、沉降深度均随满流流速的增大而线性增大;形成土拱时,沉降半径、沉降深度随流速增大的扩展速度(VL、VH)与D/d50呈对数关系;溃砂时,沉降半径随流速增大的扩展速度VL规律如下:当23.0≥D/d50≥6.0时,VL随D/d50的增加而线性增大,当42.0≥D/d50≥23.0时,VL随D/d50的增大呈对数减小。Aiming at the problems of ground settlement induced by the underground pipeline damage in water-rich sand layer,a set of visualization experimental device was designed.For these cases of 11 kinds of sand samples with particle size of skeleton d90=1.458.45 mm and 5 kinds of full pipe flow velocity,the law of ground settlement induced by seepage erosion was studied.Research show that:1)There are three modes of seepage erosion induced by pipeline damage:only water inrush without settlement,soil arching formation with settlement and sand crushing with settlement;2)The particle size of soil skeleton,damaged mouth size and thick-span ratio are the main factors to determine the seepage erosion mode of soil;3)When the soil arching or sand crushing is formed in the soil above the damaged mouth of pipeline,the relationship between the particle size of skeleton d90 and the thick-span ratio r is that:when 8.0≥r≥4.2,the d90 decreases parabolically with the increase of r;when 12.5≥r≥8.0,d90 remains unchanged;4)When the soil arching or sand crushing is formed in the soil above the damaged mouth of pipeline,the initial settlement radius and settlement depth with the flow velocity equal to 0 are determined by the ratio(D/d50)of the damaged mouth diameter D and the average particle size of soil d50;the settlement radius and depth increase linearly with the increase of full pipe flow velocity;when the soil arching is formed,the expansion velocity(VL、VH)of settlement radius and settlement depth with the increase of flow velocity is logarithmic to D/d50.When the sand crushing is formed,the expansion velocity VL of settlement radius with the increase of flow velocity is that,when 23.0≥D/d50≥6.0,it increases linearly with the increase of D/d50;when 42.0≥D/d50≥23.0,it decreases logarithmically with the increase of D/d50.

关 键 词：渗流侵蚀 沉降 厚跨比 流速 粒径 

分 类 号：TU470[建筑科学—结构工程]