基于新型电动装置的真空-电渗联合加固滩涂软土地基的试验研究

Experimental study on reinforcement of marine clay foundation based on new electrokinetic device using combined vacuum preloading and electro-osmosis consolidation

沿海地区滩涂软土由于承载力低、压缩性高,出现了从地面沉降到结构严重破坏等一系列岩土工程问题。本文利用自制研发的一种新型电动装置,将真空预压系统与电渗排水固结系统结合,充分利用2种方法的优点联合加固沿海滩涂软土。通过真空预压、真空-电渗和真空-间歇电渗3组室内试验验证新型电动装置与真空预压-电渗联合加固法的有效性,确定针对滩涂软土的最佳加固方法。结果表明:与真空预压和真空-电渗相比,真空-间歇电渗的孔隙水压力变幅较大,且土体沉降更大。同时,真空-间歇电渗加固后的土体抗剪强度和承载力较高,加固效果更加均匀。真空-间歇电渗能显著改善滩涂软土的力学性能,其排水效率较高,能够为滩涂软土联合加固技术的应用提供一定的理论依据。

Geotechnical problems,ranging from ground settlement to severe structural damage,have arisen for marine clay in the coastal regions due to its low bearing capacity and high compressibility.An electro-osmotic consolidation combined with vacuum preloading was investigated on the marine clay in this study using a new electrokinetic device.The combined method with the prefabricated device connecting the electro-osmotic system to the vacuum preloading system was designed to take full use of advantageous merits of each system for efficient soil improvement.Three groups of laboratory tests of vacuum preloading(VP),vacuum preloading with electro-osmotic consolidation(VE),and vacuum preloading with intermittent electro-osmotic consolidation(VIE)were conducted on marine clay to examine the effectiveness of the proposed combined method and identify an optimal soil improvement technique.The results indicated that the VIE varied pore water pressure greatly and produced the larger soil settlement compared to VP and VE.Furthermore,the treated soil had higher shear strength and bearing capacity with a uniform consolidation effect at the soil cross-section after testing.The VIE technique significantly improved the mechanical properties of marine clay with a higher water removal efficiency during the treatment process.This research study provides useful information for the design guide and practical application of the combined technique for the marine clay.