烧料礓石改性浆体–遗址土体界面抗剪性能试验

Experiment on shear resistance behavior of interface between slurry modified by calcined ginger nuts and soil mass of earthen sites

为研究土遗址锚固系统中浆体–土体界面抗剪性能,揭示锚固系统内部受力机制。试验选择目前土遗址锚固工程中常用的烧料礓石、粉煤灰、石英砂及遗址土作为主要浆体材料,同原状遗址土制成黏结试样。根据实际工作条件,对试样进行室外土体掩埋养护。通过浆体–土体界面直接剪切试验,得到不同配比浆体–土体界面的剪应力–位移关系曲线、抗剪强度参数及浆体–土体界面剪应力–位移拟合曲线。试验结果表明,浆体–土体界面未能有效黏结,界面抗剪强度主要依靠滑动摩擦及咬合摩擦承担;烧料礓石改性遗址土浆体与遗址土体黏结试样内摩擦角最大,浆体材料兼容性对界面抗剪强度的提高具有重要意义。室外掩埋养护土体温湿度的频繁波动和PS溶液的固化作用对界面黏结能力影响显著。因此,土遗址锚固工艺是保证锚固质量的关键因素之一。

To explore the shear resistance behavior of grout-soil interface in anchoring conservation of earthen sites and reveal the internal mechanical mechanism of anchorage system,calcined ginger nuts,fly ash,quartz sand and soil from earthen sites which are commonly used in anchoring engineering are selected as the main grout materials. Bonded samples were made by grout and undisturbed soil from earthen sites. Regarding the actual environment at which the anchor system survives,all the samples were buried and maintained in outdoor soil mass. The relationship between shear stress and displacement,strength parameters,and a new fitting formula were gained by direct shear test. The results show that slurry and soil fail to bond,interfacial shear strength should rely on sliding friction and particles interlock capacity. The mixing slurry of calcined ginger nuts with earthen sites＇soil presents the largest inner friction angle,which means that compatibility between slurry and soil is of important significance to improve shear strength of interface. Owing to the large variation of temperature and moisture and consolidation of grout-soil interface by PS solution,shear resistance of grout-soil interface is to some extent weakened. The experimental results reveal that anchor craft of earthen sites plays an important role in the improvement of shear strength.