土遗址裂隙加固桩-浆协同效果与机制研究

Researches on Synergistic Effect and Mechanism of Pile-slurry for Reinforcement of Fissure Grouting in Earthen Sites

既往研究表明以生石灰为掺料的浆液与土遗址兼容性良好,并且发现在此类浆液中添加微型石灰桩能够更好地消除浆–土界面的干缩分异现象。因此,为探究桩–浆协同作用下裂隙的加固效果与机制,开展单独注浆工艺和宽径比(裂隙宽度与石灰桩直径的比值)为1.5、2.0、2.5和3.0的桩–浆协同工艺下室内遗址土裂隙注浆试验。首先,在浆液养护63 d后,对裂隙两侧等距土体的宏观性质指标(贯入阻力、密度、液塑限和颗粒组成)进行测试;然后,利用扫描电子显微镜图像、比表面积(SSA)、阳离子交换量(CEC)及土体孔隙相对变化率(Pr)对裂隙注浆后加固效果进行定性和定量联合分析。结果表明:桩–浆协同作用下,宽径比小于2.5时,裂隙两侧土体的加固效果均优于单独注浆条件。土体被加固效果随着宽径比增加先增加后减小,宽径比为2.0时效果最佳;宽径比大于3.0时,加固效果弱于单独注浆条件。结果反映了分属于石灰桩和浆液的膨胀和离子迁移对裂隙两侧土体的挤密和团聚作用不是简单的线性叠加,而是当宽径比超过2.0时,出现浆液对石灰桩的挤密和团聚作用产生了明显的抑制反馈。

Researches show that the slurry with quick lime as admixture is well compatible with earthen sites,and adding the micro-lime piles into this slurry can better eliminate shrinkage differentiation phenomenon of the slurry-soil interface.In order to explore the reinforcement effect and mechanism under the synergy of pile-slurry,fissure grouting of indoor earthen sites was carried out under single grouting technology and pileslurry synergistic reinforcement technology with the width-diameter ratio of 1.5,2.0,2.5 and 3.0(ratio of crack width to lime pile diameter).After curing for 63 days,the macro-properties(penetration resistance,density,liquid plastic limits and particle composition)of equidistant soil on both sides of the fissures were tested.Then the reinforcement effects of the soil on both sides of fissure were qualitatively and quantitatively analyzed by scanning electron microscopy,the specific surface area,cation exchange capacity and pore relative change rate of soil(Pr).The results showed that the reinforcement effect was better than that of single grouting when the width-diameter ratio was less than 2.5.The effect of soil reinforcement increased first and then decreased as the width-diameter ratio increases,and was the best when width-diameter ratio equaled to 2.0,and was weaker than that of single grouting when the width-diameter ratio was more than 3.0.The essence reflected by the results was that the compaction and agglomeration of soil on both sides of fissures caused by the expansion and ion migration of lime pile and slurry were not a simple linear superposition,but when the width-diameter ratio was more than 2.0,the slurry would obviously inhibit the compaction and agglomeration of the lime pile.