复杂岩石地层盾构掘进效能影响因素分析

ANALYSIS OF INFLUENCING FACTORS OF SHIELD TUNNELING PERFORMANCE IN COMPLEX ROCK STRATA

基于现场掘进试验和岩石点荷载强度试验,对泥岩、砂岩交互地层条件下泥水盾构的掘进效能及其影响因素进行研究。利用现场采集的数据,运用回归分析的方法,主要分析盾构掘进效能与岩石强度、刀盘推力及刀盘扭矩的关系。研究成果表明,岩石强度越高,刀盘每转切深和掘进速率就越低,二者呈幂函数曲线关系;随着刀盘推力的增大,切深呈幂函数关系增加;而随着刀盘切深的增加,刀盘扭矩则呈线性增加。对比两种地层的掘进特性,相对而言,泥岩地层掘进效能较高,但需要较大的扭矩,而在砂岩地层掘进需要较大的推力才能获得理想的掘进效能。

The purpose of mechanized shield tunneling is to increase its penetration rev and penetration rate. According to literatures, the main factors relating to shield tunneling performance are geological conditions, mechanical parameters and their compatibility. The shield tunneling performance of Chongqing Yangtze River tunnel in alternative of mudstone and sandstone bed is discussed. Based on field shield excavation tests and rock point load strength tests, shield cutter penetration rev, penetration rate and their influencing factors are studied. Using the collected in-situ data, the statistical relationships between shield tunneling performance and rock strength, cutter head thrust force and torque are analyzed by means of regression analysis. Simultaneously predicting models of penetration rev and penetration rate are established. The higher the rock strength is, the lower the cutter penetration rev and penetration rate are; and their relationship can be expressed by power function. As the cutter penetration increases, the cutter head torque increases linearly. Thought checking the shield tunneling characteristics in the two strata, the shield tunneling performance is found higher in the mudstone, but higher torque value is required. However higher thrust force is required in the sandstone if the efficient excavation is to be acquired; and the required torque is lower than that in the mudstone. This can be attributed to higher strength of the sandstone and its shallow penetration of the disc cutters.