摘要
针对吹填淤泥真空预压地基处理效果差的关键问题,全面总结了笔者及其课题组多年来的研究成果,主要包括4个方面:(1)采用超低压固结–渗透仪进行了大量的吹填淤泥固结、渗透试验,发现了初始含水率和液限对压缩–渗透性状的影响规律,建立了压缩过程中渗透系数的定量演化规律。(2)吹填淤泥真空预压过程中的位移、应变发展规律和土柱形成机理。基于粒子图像测速(PIV)技术和粒子追踪测速(PTV)技术,获得了吹填淤泥真空预压固结过程中的土体位移、应变发展规律,揭示了吹填淤泥真空预压固结机理,获得了真空预压作用下不同初始含水率和不同级配吹填淤泥的土柱形成过程。(3)吹填淤泥真空预压固结计算方法。基于不均匀应变假定提出了土柱区内、外固结计算公式,获得了不同边界真空度时空变化下的固结规律。以土柱形成过程为基础,建立了考虑土柱影响的吹填淤泥真空预压固结计算方法。(4)通过室内和现场试验,从增强真空渗流场、延缓土柱形成和改良土性等方面,优化排水板滤膜孔径,提出了分级、增压式、絮凝–真空预压等多项防淤堵处理技术,缓解排水体淤堵,提高固结速率,加速吹填淤泥处理,增强加固效果。研究成果对吹填淤泥场地开发利用,缓解城市土地资源紧张,促进城市可持续发展具有重要意义。
Considering the key problem that the vacuum preloading method cannot efficiently improve dredged slurry,the research findings over the years obtained by the author’s research team are comprehensively summarized,including the following four aspects:(1)A large number of consolidation–hydraulic conductivity tests are performed using the modified consolidation apparatus under low initial stress.Based on the test results,the influences of the initial water content and the liquid limit on the compression-permeability properties are discussed.The evolution laws of the permeability coefficient during the compression are obtained quantitatively.(2)The development laws of displacement and strain of soils and the formation mechanism of soil column during the vacuum preloading consolidation of the dredged slurry are illustrated.By utilizing the particle image velocimetry(PIV)and the particle tracking velocimetry(PTV)techniques,the development laws of the displacement and strain of soils during the vacuum preloading consolidation process are obtained.Furthermore,the consolidation process of the dredged slurry is revealed.Besides,the formation process of the soil columns under different initial water contents and particle-size distributions is obtained.(3)The analytical and numerical methods are proposed to calculate the consolidation of dredged slurries improved by vacuum preloading.Based on the uneven strain assumption,the consolidation solutions are derived for the clogging zone and the intact zone,respectively.Subsequently,the consolidation behaviors are studied under various distributions and development laws of vacuum preloading at the permeable boundaries.Besides,the consolidation model considering the formation of the soil columns is also established to investigate the relevant influences.(4)Based on the laboratory and field tests,several methods are proposed by enhancing the vacuum seepage fields,slowing the formation of soil columns,and improving the soil properties,to increase the consolidation efficiency.These methods include applying staged vacuum preloading,booster PVDs,multi-flocculant treatment,and appropriate pore size of PVD filters.Using these methods,the clogging of the dredged slurry during the treatment process can be reduced,and then the consolidation speed and improvement quality can be increased.The research findings are of great significance to developing and utilizing dredging slurry sites,alleviating the shortage of urban land resources,and promoting the sustainable urban development.
作者
蔡袁强
CAI Yuan-qiang(College of Civil Engineering,Zhejiang University of Technology,Hangzhou 310014,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2021年第2期201-225,I0003,共26页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金委对笔者相关研究的持续支持。
关键词
吹填淤泥
真空预压
固结
土柱
增压
絮凝
dredged slurry
vacuum preloading
consolidation
clogging
vacuum gradient
flocculation
