Analysis On Basement Disengagement With Ratchet Characteristic In Heavy Haul Train Tunnel

With the accelerating of China's economic construction, volume of freight logistics becomes a matter of economic lifeline; at the same time, the development of economy stimulated the demand for energy, coal accounts for power energy structure in China is quite large proportion, which makes coal transport volume continue to increase. The growing demand for materials and energy, making the heavy-haul-railway transport advantages to highlight. However, with backward design specifications, designing of the heavy haul railway tunnel depends on engineering analogy methods, for reasons of tunnel base disengagment cannot be explained. Supported by Sichuan Province science and technology support program funded projects, combining theoretical analysis with numerical simulation method, this paper introduced the ratchet effect of materials which is considered an objective phenomenon, and put its theoretical results on simulation study of tunnel basement rock disengagment phenomenon. The main research study contents and results are as follows:(1) The common soil constitutive model is compared and analyzed, and the constitutive model of rock and soil material is selected by the principle of reasonable and practical.(2) The existing ratcheting effect of materials have been compared. A constitutive model that is used to describe the ratcheting effect of geo-material framed by D-P model, Ohno-Abdel-Karim kinematic hardening rule and non-associated flow rule is established.(3) Based on ANSYS and using Fortran as a compiler language, the user material subroutine Usermat which contains the behavior of rock and soil is developed by UPFs. In order to realize the constitutive model of material in the program, the appropriate stress update process and the consistency matrix are derived. The test showed that the program can reasonably describe geotechnical material stress-strain behavior and display reasonable ratchet phenomenon.(4) The phenomenon of disengaging of the basement rock in some single track tunnel basement under load of heavy haul railway is researched with Usermat, which contributes to summarizing the disengaging of tunnel basement and concluding its law of development.