桩基后压浆工艺在高速铁路岩溶地区的应用

桩基后压浆工艺是成桩时在桩身桩端预置压浆管路和压浆装置，待桩身达到一定强度后，通过压浆管路，采用高压注浆泵压注的浆液对桩端沉渣及桩侧泥皮进行固化，提高桩的承载力，减少沉降量，达到提高桩身质量的目的。目前，通过后压浆工艺提高桥梁桩基承载力在高速铁路领域尚鲜有应用。京沈高铁顺义特大桥#189，#190墩地处岩溶地区，原设计桩长需穿越大量溶洞区域，施工难度剧增，投资成本巨大，现通过桩基后压浆工艺，缩短桩长，提高了基桩承载力。现场静载试验证明:后压浆能够显著提高基桩承载力，减少沉降量，既能在京沈高铁沿线岩溶地区进行应用，又使桩基避开溶洞区域，降低施工难度。

Application of Post Grouting Technology of Pile Foundation in Karst Area of High Speed Railway

The post grouting technology of pile foundation is a process that preset grouting pipeline and grouting device at the pile and pile ends, solidifying pile bottom sediment and pile side mud by grouting piping and high pressure grouting pumps, to achieve the purpose of improving the pile bearing capacity, reducing the settlement and improving the quality of the pile. Now we shorten the pile length and improve the pile bearing capacity by post grouting technology of pile foundation. At present, there is still little application to improve the bearing capacity of bridge piles by the post-grouting process in the field of high-speed railway. #189, #190 pier of Shunyi Bridge of Beijing-Shenyang high-speed railway is located in karst areas, the original design of pile length requires to traverse a large cave area, bringing difficulties in construction and investment cost control. Field static load test proved that the post grouting process can significantly improve the bearing capacity of the pile foundation and reduce the settlement, which can be popularized and applied in the karst area along the Beijing-Shenyang high-speed railway and avoid the cave areas to reduce the construction difficulty.