板岩流变特性试验与模型辨识

Rheological Tests of Slate and Model Identification of Rock

摘要:

针对江西武吉高速公路隧道的Ⅱ～Ⅴ级围岩，通过分级增量循环加卸载试验、剪切流变试验和双轴压缩流变试验研究围岩的流变特性，并对模型进行辨识。试验结果表明Ⅱ～Ⅳ级围岩具有过渡蠕变和定常蠕变过程，表现为脆性破坏；Ⅴ级围岩则具有过渡蠕变、定常蠕变和加速蠕变过程，表现为塑性破坏。通过模型辨识，采用广义Kelvin模型模拟Ⅱ～Ⅳ级围岩，采用非线性流变元件NRC模型与西原模型的串联模型模拟Ⅴ级围岩，可较好模拟围岩流变特性；同时得到与应力水平有关的围岩流变力学参数。模型辨识的方法可应用于板岩以外的其他岩石。

Abstract:

Circular increment step load and unload test, shear rheological test and two-axes compression test were carried out to study the rheological properties based on Ⅱ-Ⅴ grade surrounding rock of Wuji highway tunnels in Jiangxi Province. The tests results showed that Ⅱ-Ⅳ grade surrounding rock contained two creep sections, namely transitionary creep and stability creep, and the failure behavior of the rock is brittle fracture.Ⅴ grade surrounding rock contained three creep sections, namely transitionary creep, stability creep and accelerating creep, and the failure behavior of the rock is plastic yield. Ⅱ-Ⅳ grade surrounding rock could be reasonably simulated with generalized Kelvin modal through the modal identification, while Ⅴ grade surrounding rock was well agreed with the nonlinear modal. Rheological parameters related to stress level were also obtained by modal identification. The method of modal identification could be applied to other rock beyond slate.