含粉砂层软土地基真空预压密封性及现场试验研究  

Vacuum preloading sealing performance and field test of soft soil foundations with silty sand layer

作　　者：符洪涛[1,2,3,4] 王晓峰 温作佳 高紫阳[1,2,5] 王军 李校兵[1,2,3,4] 叶舒翔[6] 林忠哲 FU Hongtao;WANG Xiaofeng;WEN Zuojia;GAO Ziyang;WANG Jun;LI Xiaobing;YE Shuxiang;LIN Zhongzhe(College of Civil Engineering and Architecture,Wenzhou University,Wenzhou,Zhejiang 325035,China;Key Laboratoryof Engineering and Technology for Soft Soil Foundation and Tideland Reclamation of Zhejiang Province,Wenzhou University,Wenzhou,Zhejiang 325035,China;Zhejiang Engineering Research Center of Disaster Prevention and Mitigation for CoastalSoft Soil Foundation,Wenzhou University,Wenzhou,Zhejiang 325035,China;Collaborative Innovation Center of TidelandReclamation and Ecological Protection,Wenzhou University,Wenzhou,Zhejiang 325035,China;International CooperationBase for Science and Technology on Ultra-soft Soil Engineering and Smart Monitoring,Wenzhou University,Wenzhou,Zhejiang 325035,China;Wenzhou Education Bureau,Wenzhou Education Infrastructure Center,Wenzhou,Zhejiang 325035,China)

机构地区：[1]温州大学建筑工程学院,浙江温州325035 [2]温州大学浙江省软弱土地基与海涂围垦工程技术重点实验室,浙江温州325035 [3]温州大学滨海软土地基防灾减灾技术浙江省工程研究中心,浙江温州325035 [4]温州大学浙江省海涂围垦及其生态保护协同创新中心,浙江温州325035 [5]温州大学浙江省超软土工程技术与智能化监测国际科技合作基地,浙江温州325035 [6]温州市教育局温州市教育基建中心,浙江温州325035

出　　处：《岩石力学与工程学报》2024年第10期2581-2589,共9页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(52325806,52178348);温州市科技项目(S2023002)。

摘　　要：针对含有高渗透性含砂层软土地基采用真空预压处理时,设置黏土密封墙是保持真空系统密封性的有效措施。粉砂夹淤泥在微观上呈现絮状结构,取土扰动对土体渗透性影响较大。通过室内渗透–固结试验,建立土体渗透系数(k_(v))与有效应力(σ′)、黏粒含量(N_(c))的关系式,作为打设密封墙的评判依据,进而在该类地基上开展不同排水板(PVD)间距的真空预压现场试验,试验结果表明:考虑上覆土压力(σ′)作用,粉砂夹淤泥的渗透系数小于10^(-5 )cm/s;膜下真空度维持在83 k Pa左右,真空系统密封性良好,表明该类地基无须打设密封墙;加固后含水率降低了20%,淤泥孔隙比降低了30%;十字板剪切强度提高了22.3~32.23 k Pa。When using vacuum preloading for soft soil foundations that contain high permeability sand layers,it is effective to establish a clay sealing wall to maintain the integrity of the vacuum system.The silt mixed with silt forms a flocculent structure at a microscopic level,which significantly affects the soil permeability when subjected to external disturbance.Experiments were conducted to determine the relationship between soil permeability coefficient(k_v),effective stress(σ′),and clay content(N_c).This relationship can be used as a basis for evaluating the construction of sealing walls.Subsequently,field tests were conducted on this type of foundation with different PVD spacing.The test results revealed that the permeability coefficient of silty sand and silt is less than 10~(-5) cm/s,considering the effect ofσ′.The vacuum pressure under the membrane was maintained at around 83 k Pa,indicating good sealing performance of the vacuum system and suggesting that a sealing wall is unnecessary for this type of foundation.After reinforcement,the moisture content is reduced by 20%and the void ratio of silt is reduced by30%.The vane shear strength increased by 22.3–32.23 k Pa.

关 键 词：地基基础 粉砂夹淤泥 真空预压 密封性 现场试验 PVD间距 

分 类 号：TU47[建筑科学—结构工程]