以新线引入既有客运专线车站软土地基加固工程为依托,开展布袋注浆桩试桩研究,分析不同浆液配比布袋注浆桩复合地基加固效果,对布袋注浆桩施工工艺、质量检验进行了研究.结果表明:布袋注浆桩机械设备高度低,对既有线影响小,对于空间受限的邻近营业线地基加固工程适用性强;提高单位面积布袋质量、采用桶式钻头引孔等可解决碎石成分类填土地基应用布袋注浆桩技术时遇到的布袋破裂、塌孔等问题.浆液质量配比水泥:水:粉煤灰 = 0.70:0.55:0.45时桩身无侧限抗压强度平均值9.6 MPa,加固效果优于高压旋喷桩;采用低应变反射波法检测桩体完整性效果较差,工程应用中应加强桩身取芯检测.
Based on the soft soil ground treatment project of the existing passenger dedicated-line station introduced by the new line,research on bag grouting pile test was carried out.The reinforcement effect of composite foundation with different grout ratios of bag grouting piles were analyzed,and the construction technology and quality inspection of bag grouting piles were studied.The results show that the mechanical equipment of the bag grouting pile is relatively low,has little impact on the existing railway line,which is suitable for the ground treatment project of adjacent operating railway lines with limited space.The problems encountered during the application of bag grouting pile technology in the classification of crushed stone filled soil foundation,such as bag breakage and hole collapse,which can be solved by improving the quality of the bag per unit area and using bucket type drill bit for hole drilling.When the grout mass ratio of cement : water : fly ash = 0.70 : 0.55 : 0.45,the average unconfined compressive strength of the pile body is 9.6 MPa,and the reinforcement effect is better than that of high-pressure rotary jet grouting piles.The use of low strain reflection wave method to detect the integrity of pile body has poor results,so the core testing of pile body should be strengthened in engineering applications.