高压旋喷修复中水溶性药剂径向迁移规律研究  

Radial migration of water-soluble agents in high-pressure rotary jetting remediation

作　　者：张文杰[1] 贾志伟 秘永宝 ZHANG Wenjie;JIA Zhiwei;MI Yongbao(School of Mechanics and Engineering Science,Shanghai University,Shanghai 200444,China)

机构地区：[1]上海大学力学与工程科学学院,上海200444

出　　处：《岩土工程学报》2023年第5期1017-1023,共7页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(41772300)。

摘　　要：高压旋喷修复是近年来出现的污染土原位修复技术,目前对于旋喷药剂的迁移规律尚不明确,工程实践缺乏可靠的理论指导。分别以荧光素钠及氯离子为示踪剂,开展不同旋喷参数下的现场及室内高压旋喷试验,并结合数值模拟研究了射流作用及对流-扩散作用下的药剂径向迁移规律。现场旋喷5 d后的结果表明,药剂质量浓度沿径向逐渐降低,分布受旋喷参数影响明显,现场最佳旋喷参数组合为注入压力25 MPa、旋转速度22 r/min、提升速度25 cm/min、喷嘴直径1.6 mm、旋喷2次。室内旋喷试验和数值模拟表明,射流作用下混合区内药剂质量浓度线性减小,喷嘴附近相对质量浓度为0.54~0.91;混合区半径随注入压力、喷嘴直径及旋喷次数的增加而增大,随旋转速度的增加而减小;药剂质量浓度及径向均匀性与旋转速度、喷嘴直径及旋喷次数呈正相关,对流-扩散作用下的药剂迁移使混合区内质量浓度降低,扩散区质量浓度升高,径向分布趋向均匀;虽然孔压消散仅需短短几分钟,但其引起的对流在约30 d内对药剂迁移起主导作用,之后扩散变为主要作用。The high-pressure rotary jetting(HPRJ)is a new technology for the in-situ remediation of contaminated soils.However,the radial migration of water-soluble remediation agents in HPRJ is still not clear,resulting in a lack of reliable theoretical guidance in engineering practice.The laboratory and in-situ HPRJ tests as the well as numerical simulations are performed using the sodium chloride and fluorescein sodium as the tracers to investigate the radial migration and distribution of agents under the effects of jet and advection-diffusion.The results of the in-situ tests after 5 d show that the agent concentration decreases along the radial direction and is significantly affected by the rotary jetting parameters.The optimum combination of the rotary jetting parameters is an injection pressure of 25 MPa,a lifting speed of 25 cm/min,a rotation speed of 22 r/min,a nozzle diameter of 1.6 mm and jetting of twice.The laboratory tests and the numerical simulations show that concentration of the agent in the mixing zone decreases linearly,with a relative concentration of 0.54 to 0.91 near the nozzle.The radius of the mixing zone increases with the increase in the nozzle diameter,injection pressure and the number of jetting times,and decreases with the increasing rotation speed.The agent concentration and radial uniformity are correlated positively with the rotation speed,nozzle diameter and the number of jetting times.The migration of the agent due to advection and diffusion reduces the agent in the mixing zone and increases the agent in the diffusion zone,and homogenizes the radial agent distribution.The advection only lasts for a few minutes,however,it dominates the agent migration in the first 30 d,and thereafter the diffusion becomes more important.

关 键 词：高压旋喷 室内试验 水溶性药剂 径向迁移 对流-扩散 

分 类 号：TU443[建筑科学—岩土工程]