Analytical solution of circular tunnel in elastic-viscoplastic rock mass

Abstract

This paper deals with a deep circular tunnel excavated in infinite homogeneous and isotropic elastoviscoplastic rock mass subjected to a hydrostatic initial stresses. The tunnel is divided into the initial plastic, viscoplastic, and elastic zones. By combining the generalized Bingham model with Mohr-Coulomb yield criteria, analytical solutions of the circular tunnel are derived with the consideration of non-associated flow rule and elasto-viscoplasticity. The initial plastic zone is defined as the instantaneous change of rock mass excavation. Based on the initial plastic zone, the stresses in viscoplastic zone are transferred to the deep surrounding rock with time due to the initial earth stresses. The results are compared with the elastic-brittle solution at static conditions, and the solutions of this paper are validated. Moreover, the presented results shows that the stress and displacement of the surrounding rock varies with time, and the solutions can be obtained at different instants of time.

An analytical solution for stresses and deformations of tunnels in a non-uniform stress field based on strain-softening model and Mogi-Coulomb criterion

“…Accurate calculations for stresses and deformations of the surrounding rock play an important role in evaluating tunnel stability and designing the support system (Cui et al 2015, Mohammad andAhmad 2016). In early work, Park (2015), Park and Kim (2006), Sharan (2003Sharan ( , 2008, and Wang et al (2019) analyzed the stresses and strains of the surrounding rock by regarding the stress condition of tunnels as a uniform stress field for simplicity. However, considerable field measurements have indicated that the insitu stress in the horizontal and vertical directions vary due to the faults, folds and other geological structures in underground coal mines (Wang et al 2000, Zhao et al 2013.…”

Tünel Projelendirilmesinde Kullanılan Yöntemler (Ampirik, Analitik ve Nümerik Yöntemler), Kısıtlamaları, Karşılaştırılması ve Öneriler

“…Analitik çözümler Kirsch [17], Kastner [18], Sulem vd. [19] Hoek ve Brown [15] Hoek [20], [21] gibi araştırmacılar tarafından geliştirilmiştir. Analitik yönteme göre ortam homojen ve izotrop kabul edilir.…”

“…Kaya kütle sistemlerine bağlı olarak analitik çözümlerde 1900'lü yıllardan itibaren gelişmeye başlamıştır. Bu yöntemlerde ortamın izotrop, homojen ve tünelin dairesel olduğu prensipler üzerinden gidilerek tünel çevresinde ve zeminde deformasyon gerilme ilişkileri elde edilmiştir [17], [18], [19], [20], [21].…”

Assessment of long-term deformation of a tunnel in soft rock by utilizing particle swarm optimized neural network

“…As a first step in applying the neural network, 125 (i.e. 5 3 being possible number of combinations, where '5 ′ represents a number of predefined values for each parameter, while '3 ′ represents number of parameters) numerical analyses were carried using the following sets of input parameters: The possible range of selected input parameters for soft rock was based on their actual range obtained from the literature (Guan et al, 2009;Weng et al, 2010;Sharifzadeh et al, 2013;Mahdevari and Bagherpour, 2014;Hamza and Stace, 2018;Paraskevopoulou and Diederichs, 2018;Wang et al, 2019;Huang et al, 2020), and the range was additionally extended, so that upper and lower boundary of each parameter range can be considered as sufficient to estimate the most probable parameter value in the subsequent analysis. These 125 sets of rheological parameters were applied to the same numerical model, which then proceeds to the calculation of long-term behavior.…”