混合土挤压固化预制桩的配方研究  

Formula experiment study on mixed soil of precast pile with extrusion method

作　　者：黄生根[1] 夏钊 雷美清[2] 陈达芬 

机构地区：[1]中国地质大学工程学院,湖北武汉430074 [2]中国科学院武汉岩土力学研究所,湖北武汉430071

出　　处：《岩石力学与工程学报》2017年第A02期4297-4303,共7页Chinese Journal of Rock Mechanics and Engineering

摘　　要：混合土挤压固化预制桩是用于软基处理的一种新技术,该技术利用泥土桩挤压机对拌和均匀的混合土料压制成型,再养护成单节桩。试验设计制作不同配方的单节桩共17根,在土料最优含水量条件下挤压成型,当达到28 d龄期后进行无侧限抗压强度和水稳定性测定。根据试验结果得到以下规律:(1)不掺石灰或低石灰掺入比情况下,试样强度随水泥掺入比增大而增大;在石灰掺入比较高的情况下,随着水泥掺入比的增加,试样强度先增大后减小;(2)在不掺水泥或低水泥掺入比情况下,试样强度随石灰掺入比增大而增大。但在水泥掺入比较大(4%,6%)的情况下,试样强度先减小后增大,在3%处出现拐点;(3)水稳定试验表明,在水泥掺入比为2%和4%时,试样的水稳定性良好,且石灰的掺入比越大,强度维持系数越大。不同试样在浸水10 d或20 d内,强度下降较快,但在浸水20 d后强度趋于稳定。根据配方中水泥或石灰的掺入比与试样强度、水稳定性的规律关系,选出了混合土挤压固化预制桩的最佳配方为水泥2%+石灰7%,可为混合土挤压固化预制桩推广应用提供依据。The mixed soil of precast pile with extrusion method is a new technique for soft foundation treatment.A single pile is pressed with the mixed soil in a soil extruding pile machine and then maintained.A total of 17 single piles of different recipes were designed and extruded under the optimal water content of soil.These piles were measured for unconfined compressive strength and water stability after 28 days.According to the test results,we found laws including：（1） The strength of the sample increased with the cement incorporation ratio when no or little lime was mixed,but decreased after an increase when adopting a relatively high lime incorporation ratio.（2） The strength of the sample increased with the lime incorporation ratio when no or little cement was mixed,but increased at 3% point after a decrease under a condition of comparable high cement incorporation ratio（4%,6%）.（3） The water stability test showed that the water stability of the sample reached a good state with a 2% or 4% cement incorporation ratio.The strength maintenance coefficient increased with the increasing lime mixing ratio.The strength of different samples decreased fast in a 10-day or 20-day immersion but then tended to be stable after that.Based on the results mentioned above,the best formula for the pile of mixed soil was selected as cement 2% ＋ lime 7%.This formula can provide support for the popularization and application of mixed soil of precast pile with extrusion method.

关 键 词：基础工程 地基处理 混合土挤压固化预制桩 配比试验 无侧限抗压强度 水稳定性 

分 类 号：TU473[建筑科学—结构工程]