Liang Wang

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Wang

First Name

Liang

ORCID

0000-0002-2663-623X

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Publications 1 - 10 of 11

Modelling rockbursts around a deep tunnel based on the particle finite element method: From progressive degradation to catastrophic ejection
Wang, Liang; Lei, Qinghua (2025)
International Journal of Rock Mechanics and Mining Sciences
We develop a novel computational framework based on the particle finite element method for simulating rockburst phenomena, from pre-failure initiation to failure evolution and to post-failure mobilisation and ejection, across spatiotemporal scales in hard rocks. The proposed framework builds upon a rigorously validated and extensively calibrated particle finite element model, distinguished by its unique capability to handle large deformation problems. This framework can simultaneously capture the creep damage mechanism based on a time-dependent strength degradation model and the brittle fracturing process based on a cohesion loss-frictional strengthening model. The post-failure mobilisation is further governed by a frictional weakening formulation to capture the associated stress drop behaviour. We consider the intrinsic material heterogeneity assuming a Weibull distribution of rock mass properties and represent the nearby fault zone as a thin continuum layer with equivalent mechanical properties. We apply the model to investigate the processes and phenomena of deep tunnelling-induced rockbursts under different stress and heterogeneity conditions. Our simulation results, grounded in a thoroughly validated modelling framework, yield insights with important implications for understanding and predicting catastrophic rockbursts during deep tunnel excavation. While further site-specific calibration would be required for practical application, the current framework demonstrates strong potential as a predictive tool for evaluating rockburst hazards in complex geological settings.
Modelling the pre- and post-failure behaviour of faulted rock slopes based on the particle finite element method with a damage mechanics model
Wang, Liang; Lei, Qinghua (2023)
Computers and Geotechnics
We develop a novel numerical model incorporating a damage mechanics formulation into the particle finite element method for analysing the pre- and post-failure behaviour of faulted rock slopes. In this computational framework, the stress-driven strain localisation and damage evolution are modelled based on an isotropic damage model; discontinuity structures like fault zones are represented as thin continuum layers with equivalent mechanical properties; the particle finite element method is used to solve and track the large deformation of rock masses. In the paper, we first present the mathematical formulation of the proposed model in the context of the Hellinger-Reissner variational principle. We conduct a thorough validation of our model for simulating the damage of brittle materials against well-documented experimental datasets of different failure scenarios. We then apply the model to simulate the deformation and failure phenomena of faulted rock slopes including both the pre-failure progressive damage and post-failure transient runout, demonstrating the strong capability of our model in physically capturing the initiation, evolution, and consequence of catastrophic rock slope failure across multiple temporal scales. In addition, our simulations can realistically reproduce the slope displacement time series with the interplay between rock damage and fault reactivation explored. The present work has important implications for understanding the physical mechanisms that drive the progressive destabilisation and catastrophic failure phenomena of rock slopes in nature.
An implicit 3D nodal integration based PFEM (N-PFEM) of natural temporal stability for dynamic analysis of granular flow and landslide problems
Zhang, Yujia; Zhang, Xue; Nguyen, Hoang; et al. (2023)
Computers and Geotechnics
The particle finite element method (PFEM) is a robust approach for modelling large deformation problems with free surface evolution. The classical PFEM, however, requires variable mapping from old to new quadrature points when adopting history-dependent material models in granular flow and landslide problems. Although the nodal integration technique circumvents this issue, it makes the PFEM temporal instable in dynamic analysis when using a displacement-based formulation. In this study, we developed a new version of a three-dimensional (3D) Nodal integration based PFEM (N-PFEM) using a mixed variational principle with the final problem resolved in mathematical programming. The proposed N-PFEM not only inherits the benefit from the nodal integration scheme that no variable mapping is required for handling history-dependent models but also is naturally temporal stable requiring no ad-hoc stabilization technique. We simulated a series of benchmark problems to demonstrate its nature of temporal stability as well as other admirable features such as the volumetric-locking free property and capability for tackling extreme configuration changes. Additionally, its application to a 3D landslide with a sensitive clay layer is shown to highlight its robustness.
Implementation of a damage mechanics model into the particle finite element method for rock slope failure analysis
Wang, Liang; Lei, Qinghua (2022)
Proceedings of the 56th U.S. Rock Mechanics/Geomechanics Symposium
We implement a damage mechanics model into the particle finite element method to simulate the pre- and post-failure processes of rock slopes. In this computational framework, the stress-driven strain localisation and damage evolution are modelled based on a continuum damage mechanics model; discrete discontinuities like faults are represented as thin continuum layers of equivalent properties; the particle finite element method is used to solve and track the large deformation of rock masses. In the paper, we first present the mathematical formulation of the proposed model and then conduct a thorough validation of our model for simulating damage propagation against well-documented experimental data. We further apply the model to simulate progressive failure phenomena of a naturally faulted rock slope including both the pre-failure degradation and post-failure runout, demonstrating the strong capability of our model in capturing the emergence, evolution and consequences of catastrophic rock slope failure. Our work has important implications for understanding the physical mechanisms driving the progressive destabilisation and catastrophic failure phenomena of faulted rock slopes in nature.
Formulation for wave propagation in dissipative media and its application to absorbing layers in elastoplastic analysis using mathematical programming
Wang, Liang; Zhang, Xue; Tinti, Stefano (2023)
International Journal for Numerical Methods in Engineering
In this article, we propose a new solution scheme for modeling elastoplastic problems with stress wave propagation in dissipative media. The scheme is founded on a generalized Hellinger-Reissner (HR) variational principle. The principle renders the discretized boundary-value problem into an equivalent second-order cone programming (SOCP) problem that can be resolved in mathematical programming using the advanced optimization algorithm-the interior point method. In such a way, the developed method not only inherits admirable features of the SOCP-based finite element method in solving elastoplastic problems but also enables the enforcement of absorbing layers (i.e., Caughey absorbing layer), which is essential in modeling stress wave propagation problems, to absorb wave energy. The proposed scheme is validated via the comparison between analytical and numerical results for seismic wave propagation in dissipative media. Its application to elastoplastic dynamic problems with stress wave propagation is also illustrated to demonstrate its efficiency.
A nodal integration-based particle finite element method for poro-elastoplastic modelling of saturated soils using mathematical programming
Wang, Liang; Zhang, Xue; Geng, Xueyu; et al. (2023)
Mechanisms of Reservoir Impoundment-induced Large Deformation of the Guobu Slope at the Laxiwa Hydropower Station, China: Preliminary Insights from Remote Sensing and Numerical Modelling
Lesche, Moritz; Wang, Liang; Manconi, Andrea; et al. (2024)
Environmental Engineering Science ~ Engineering Geology for a Habitable Earth: IAEG XIV Congress 2023 Proceedings, Chengdu, China. Volume 4: Technological Innovation and Application for Engineering Geology
The construction/operation of ultrahigh arch dams may impose significant perturbations to surrounding mountains, resulting in landslide motions of rock slopes and endangering the safety of hydropower systems and human habitats. For example, the Laxiwa Hydropower Station in China witnessed its nearby Guobu slope displacing significantly after the reservoir impoundment and having so far displaced up to ~40 m. It is of great importance to understand the mechanisms driving this large deformation. Here, we present some preliminary results from a combined remote sensing and numerical modelling investigation of this slope before, during, and after the reservoir impoundment. Analysis based on the differential interferometric synthetic aperture radar (DInSAR) data indicates that the slope had already been actively creeping at a rate of ~10 cm/year (e.g. in years of 2003-2005). We develop a geological model including different rock mass compartments and various discontinuity structures as well as a realistic representation of the suspended ancient landslide. We model the coupled hydro-mechanical and creep behaviour of the slope in response to reservoir impoundment. A good agreement is reached between the simulation results and field measurements of slope displacement time series recorded at different elevations of the slope surface. Our results show that the reservoir impoundment causes notable pressure changes at the toe region of the slope, leading to strong deformations (under coupled poroelastic and primary creep effects) that propagate upslope with the ancient landslide partially reactivated. These deformations tend to decelerate significantly after the impoundment due to the transition to secondary creeps.
A three-dimensional particle finite element model for simulating soil flow with elastoplasticity
Wang, Liang; Zhang, Xue; Lei, Qinghua; et al. (2022)
Acta Geotechnica
Soil flow is involved in many earth surface processes such as debris flows and landslides. It is a very challenging task to model this large deformational phenomenon because of the extreme change in material configurations and properties when soil flows. Most of the existing models require a two-dimensional (2D) simplification of actual systems, which are however three-dimensional (3D). To overcome this issue, we develop a novel 3D particle finite element method (PFEM) for direct simulation of complex soil flows in 3D space. Our PFEM model implemented in a fully implicit solution framework based on a generalised Hellinger–Reissner variational principle permits the use of a large time step without compromising the numerical stability. A mixed quadratic-linear element is used to avoid volumetric locking issues and ensure computational accuracy. The correctness and robustness of our 3D PFEM formulation for modelling large deformational soil flow problems are demonstrated by a series of benchmarks against analytical or independent numerical solutions. Our model can serve as an effective tool to support the assessment of catastrophic soil slope failures and subsequent runout behaviours.
An implicit nodal integration-based PFEM for dynamic analysis of saturated porous media
Wang, Liang; Zhang, Xue; Lei, Qinghua (2023)
Nodal integration-based particle finite element method (N-PFEM) for poro-elastoplastic modelling of saturated soils under large deformation
Wang, Liang; Zhang, Xue; Geng, Xueyu; et al. (2023)
Computers and Geotechnics
This paper presents the nodal integration-based particle finite element method (N-PFEM) for poro-elastoplastic analysis of saturated soils subject to large deformation, utilising the generalised Hellinger-Reissner variational principle to reformulate the governing equations for saturated soil dynamics into a min–max optimisation problem. With finite element discretisation and nodal integration over cells, the problem is transformed into a standard second-order cone programming problem, efficiently resolved using the advanced primal–dual interior point method. The N-PFEM method has several advantages, including the use of linear triangular elements without volumetric locking issues, the avoidance of regularisation techniques, and the elimination of tedious variable mapping after remeshing. The numerical model is validated for large deformation analysis of saturated soils with a series of benchmarks against available analytical and numerical solutions, with a case study of the deformation of an embankment considering stone column reinforcement also carried out. This N-PFEM framework offers an effective and efficient simulation approach for the evolutionary behaviour of saturated soils with large deformation in complex geotechnical configurations of practical relevance.

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Liang Wang

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