松散地层脉动与稳压灌浆室内试验研究

An indoor experimental study of loose soil strata pulsating and regulated filling

开展松散地层控制灌浆工艺研究具有重要的工程实践意义。开发了一套室内松散地层灌浆模拟试验装置,可模拟受灌体弹塑性边界,对比进行稳压灌浆与脉动灌浆试验。试验结果表明,在相同围压(0.2 MPa)、水固比(0.6)、不同灌浆压力(0.1,0.2,0.4 MPa)条件下,脉动灌浆灌后结石体7 d强度明显优于稳压灌浆,且强度值分布较均匀。电镜扫描表明,脉动灌浆后的土体呈团状结构,较常规灌浆后的絮状结构更紧密。脉动灌浆参数影响试验表明,采用较大的脉动灌浆压力有利于受灌体挤密,但压力过大更易劈裂扩散,造成浆脉变薄、结石强度降低;采用较小的水固比不利于浆液的扩散,但水固比过大会导致结石体厚度变薄、强度降低。试验论证了松散地层灌浆采用脉动灌浆工艺更加适宜,但需合理控制灌浆压力和水固比。

A study of the control filling technology on loose strata grouting has a great influence on engineering project practice. The development of a set of indoor imitated test device of loose ground filling can imitate the filler＇s elastoplastic border, and tests on conventional grout filling and pulsating grout filling are carried out comparatively. The results show that under the same conditions of confining pressure （0.2 MPa）, water-solid ratio （0.6） , even under different filling pressures （0. 1,0.2 and 0.4 MPa） , the pulsating grout filling stones body＇s 7d strength is significantly better than that of the conventional grout, and the strength value is evenly distributed. SEM shows that the clods after pulsating grouting is in a round structure, its flocculent structure is closer compared with the conventional grout. The results of pulsating grout filling parametric effect test show that using a large grouting pulsating pressure helps the filler become closer, but the excessive pressure causes splitting diffusion, thin slurry pulse and a decrease in the stones strength. The use of less water-solid ratio is not conducive to the spread of the slurry, but if the water-solid ratio is excessive, the stone body will become thinner and have lower intensity. The test indicates that application of the pulsating grout filling technology to unconsolidated strata grouting is more suitable, but reasonable control of filling pressure and water-solid ratio are needed.