超高压旋喷桩取芯完整率保障技术研究

Research on Guarantee Technology of Coring Completeness of Ultrahigh Pressure Jet Grouting Pile

摘要:

某锚碇区域上覆地层主要由粉质黏土构成，表现出较低的力学强度和地基摩擦系数，塑性不足且具有较高的压缩性，地层厚度介于43.8~50.5 m。面对锚碇区基础承载力不足的挑战，项目首次采用了桥梁工程中的全断面深层地基加固技术，通过水平封底的方法对基底土壤进行改良，超高压旋喷桩的施工质量对工程的最终成败起着决定性作用。取芯检测作为评估旋喷桩施工质量的关键手段，其准确性和直观性无可替代。在取芯过程中，由于受到取芯技术、设备性能、操作人员技能以及地质环境等多重因素的影响，芯样的完整率较低。通过对比实验，筛选出一套能够提高超高压旋喷桩取芯完整率的施工技术组合，旨在提高后续试验准确性，为类似工程提供宝贵的经验和技术指导。

Abstract:

The overlying strata in an anchorage area is mainly composed of silty clay， which shows the low mechanical strength and foundation friction coefficient with the poor plasticity and higher compressibility. The thickness of the strata is 43.8m~50.5m. Facing the challenge of insufficient bearing capacity of foundation in anchorage area， the full-section deep foundation strengthening technology is firstly used in the project. The basement soil is improved by horizontal sealing. The construction quality of ultrahigh pressure jet grouting pile plays a decisive role in the final success or failure of the project. The coring detection is a key means to evaluate the construction quality of jet grouting piles. Its accuracy and intuitiveness are irreplaceable. In the coring process， due to the influence of factors such as coring technology， equipment characteristics， operating personnel skill and geological environment， the coring completeness of core sample is lower. Through the experimental comparison and research， a set of construction technical combination, which is able to improve the coring completeness of ultrahigh pressure jet grouting pile, is screened out. Its aim is to improve the subsequent experimental accuracy and provide valuable experience and technical guidance for the similar projects.