生石灰为掺料的土遗址裂隙注浆浆液结石体力学兼容性研究

Study on the mechanical compatibility of fissure grouting slurry with quick lime and grouting technology optimization in earthen sites

裂隙注浆是目前土遗址裂隙加固领域的通用手段,浆液的膨胀性和结石体与遗址土体的力学兼容性成为注浆措施能否充分发挥封堵和黏结作用的关键。研究通过对9种不同配合比及水灰比的SH-(Ca O+F+C)浆液进行膨胀性与流动性测试,最终遴选出配合比CaO:F:C=3:2:5的3种不同水灰比浆液作为优选浆液,并通过对优选浆液连续间隔龄期结石体的强度测试确定了最佳养护龄期。而后通过热膨胀和不固结不排水三轴试验,得到了浆液结石体和遗址土体的线胀系数以及浆液结石体、浆液结石体-重塑遗址土和重塑遗址土3类试样的破坏模式、应力-应变关系曲线、抗剪强度参数与弹性模量。结果表明:浆液结石体和遗址土体的线胀系数数量级别相同,3组优选水灰比浆液结石体和重塑遗址土体力学行为一致,其中配合比为CaO:F:C=3:2:5、水灰比为0.50的浆液结石体与重塑遗址土力学兼容性最佳。

Fissure grouting is a general method in the fissure reinforcement field in earthen sites. The expansibility of slurry and the mechanical compatibility between concretion and site soil are the key factors on whether the grouting measures can fulfill the role of sealing and bonding. The swelling and fluidity tests of SH-(CaO+F+C) slurry with nine different mix ratios and water cement ratios, and three different water-cement ratio slurries of the mixture ratio CaO:F:C = 3:2:5 were selected as optimum slurry. The best curing age was determined by the concretion strength test with continuous interval age. And then the thermal expansion coefficient of the grout concretion and the site soil were obtained by the thermal expansion test and the unconsolidated undrained triaxial test. The failure modes, stress-strain curves, shear strength parameters and elastic modulus of three kinds of specimens, which are grout concretion, grout concretion-remolded site soil and remolded site soil were also obtained. The results show that the thermal expansion coefficient of grout concretion and site soils are the same in magnitude. The mechanical behavior of three kinds of grout concretion and remolded site soil are consistent. Among them, the grout concretion with a mixture ratio of CaO:F:C = 3:2:5 and the water-cement ratio of 0.50 has the best mechanical compatibility with the remolded site soil.