饱和粉细砂层锚索预应力变化规律监测分析

Monitoring and analysis of variation of anchor prestress in saturated silty sand condition

锚索的预应力损失在工程建设中不可忽视,工程的场地环境条件成为影响锚索预应力损失的主因。饱和粉细砂层较其他地质条件更为复杂敏感,更易引起锚索预应力值的损失。通过对廊坊市某深基坑工程锚索预应力值的实时监测,结合工程环境,分析饱和粉细砂层中造成锚索预应力值变化的原因。结果表明,施工过程、张拉过程以及环境因素都影响锚索预应力的变化,其中开挖过程的影响最明显,预应力值的变化率最大值达79.1%;瞬时卸载造成预应力值22.8%~59.2%的损失。对饱和粉细砂层中锚索预应力变化规律的研究分析结论可为类似地质环境的工程建设提供经验。

Prestress loss of anchor cable should not be neglected in engineering construction. The cause of prestress loss is usually related to engineering site condition. The saturated silty sand is more complicated and sensitive than other geological conditions, which is more likely to cause prestress loss. Through real-time monitoring of anchor prestress of a deep foundation pit in Langfang city, combining with the engineering environment, factors influencing on variation of anchor prestress are analyzed. The results show that the process of construction, tension and environmental factors affect the variation of prestress. The most obvious impact is the excavation process; and the maximum rate of variation of prestress value is 79.1%; instantaneous unloading causes values of prestress loss between 22.8% to 59.2%. The influence of construction process is most obvious. Experience for similar geological engineering construction is provided through the research and analysis of variation law of anchor prestress.