地铁行车载荷下土体累积孔压正交试验分析

Orthogonal analysis on accumulated pore pressure of soil under subway moving loads

为研究地铁行车载荷作用下隧道周围土体孔压特性,基于正交试验设计进行了多组动三轴试验,计算并分析了累积孔压受围压、动应力幅值、频率以及振动次数因素的影响率.结果表明:含水量越大的土体,地铁行车载荷产生的累积孔压越高;累积孔压受单因素影响较大,影响率最大是动应力幅值,其次是围压、频率,最小是振动次数;围压与振动次数、频率与振动次数间的耦合作用对累积孔压影响可忽略,其他因素耦合作用均不可忽略;在一定条件下,耦合作用影响效果比单因素显著,如动应力幅值与围压耦合作用要比单因素振动次数对累积孔压的影响要大.

In order to study the characteristics of soil of pore pressure under subway moving loads,this paper calculated and analyzed the influence ratio of accumulated pore pressure with confining pressure,dynamic stress amplitude,frequency and vibration frequency by dynamic triaxial tests based on orthogonal experimental design.The results show that the water content of soil is larger,and the accumulated pore pressure is higher.The accumulated pore pressure is greatly influenced by single factor,and the greatest influence is dynamic stress.The second is confining pressure and frequency,and the last is vibration times.The coupling of confining pressure and vibration times,frequency and vibration times can be ignored to accumulated pore pressure,and the others can not be ignored.The coupling of factors is remarkable to accumulated pore pressure than the single factor under certain conditions.For example,the coupling of factors between dynamic stress amplitude and confining pressure is greater than that of vibration frequency on accumulated pore pressure.