The seepage of groundwater and the strain-softening of rock mass in a submarine tunnel expand the plastic region of rock, thereby affecting its overall stability. It is therefore essential to study the stress and strain fields in the rocks surrounding the submarine tunnel by considering the coupled effect of strainsoftening and seepage. However, the evolution equation for the hydro-mechanical parameters in the existing fully coupled solution is a uniform equation that is unable to reproduce the characteristics of rock mass in practice. In this study, an updated numerical procedure for the submarine tunnel is derived by coupling strain-softening and seepage effect based on the experimental results. According to the hydro-mechanical coupling theory, the hydro-mechanical parameters such as elastic modulus, Poisson's ratio, Biot's coefficient and permeability coefficient of rocks are characterized by the fitting equations derived from the experimental data. Then, the updated numerical procedure is deduced with the governing equations, boundary conditions, seepage equations and fitting equations. The updated numerical procedure is verified accurately compared with the previous analytical solution. By utilizing the updated numerical procedure, the characteristics of stress field and the influences of initial pore water pressure, Biot's coefficient, and permeability coefficient on the stress, displacement and water-inflow of the surrounding rocks are discussed. Regardless of the variations in hydro-mechanical parameters, the stress distribution has a similar trend. The initial permeability coefficient exerts the most significant influence on the stress field. With the increases in initial pore water pressure and Biot's coefficient, the plastic region expands, and the water-inflow and displacement increase accordingly. Given the fact that the stability of the tunnel is more sensitive to the seepage force controlled by the hydraulic parameters, it is suggested to dewater the ground above the submarine tunnel to control the initial pore water pressure. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

The majority of existing studies on the soil-geogrid interaction were based on the assumption that the surrounding geotechnical media was a homogeneous material. However, the different composition, structure and history of the geotechnical media resulted in significant differences in mechanical behavior. This discrepancy could lead to an overestimation of the pullout capacity of the soil-geogrid, which could in turn cause failures in the engineering practice. The influcence of the uncertainty of the geotechnical media on the pullout behavior of the soil-geogrid was investigated in this article. A number of groups of random distributions of the properties of soils, associated with the strain-softening constitutive model, were incorporated in the numerical simulation. The results demonstrated that the pullout behavior of the soil-geogrid, including the ultimate pullout capacity and the post-peak softening behavior, was highly impacted by the uncertainty of the mechanical properties of the surrounding inhomogenous media, in constrast to the case that with the homogeneous geotechnical media.

The pull-out capacity of plate anchor is significantly impacted by the embedment loss during keying, necessitating its prior estimation. The soil surrounding the anchor undergoes considerable disturbance during keying, but the soil softening induced by accumulated shear strains was neglected in almost all the existing numerical studies. In this paper, an elastic-perfectly plastic model with strain-softening was combined with the integraltype nonlocal method to overcome the mesh dependency in large deformation finite element simulations. The biaxial compression tests were simulated firstly and the keying process of strip anchors were reproduced by varying anchor width, thickness, loading eccentricity, undrained shear strength and sensitivity. It was observed that the ultimate embedment loss increased nearly linearly with soil sensitivity, a trend that was especially pronounced at lower loading eccentricity ratio. The generalized equations for evaluating the ultimate embedment loss were proposed and their reliabilities were verified by the existing centrifuge tests.

This paper presents an improved strain -softening constitutive model considering the effect of crack deformation based on the triaxial cyclic loading and unloading test results. The improved model assumes that total strain is a combination of plastic, elastic, and crack strains. The constitutive relationship between the crack strain and the stress was further derived. The evolutions of mechanical parameters, i.e. strength parameters, dilation angle, unloading elastic modulus, and deformation parameters of crack, with the plastic strain and con fining pressure were studied. With the increase in plastic strain, the cohesion, friction angle, dilation angle, and crack Poisson 's ratio initially increase and subsequently decrease, and the unloading elastic modulus and the crack elastic modulus nonlinearly decrease. The increasing con fining pressure enhances the strength and unloading elastic modulus, and decreases the dilation angle and Poisson 's ratio of the crack. The theoretical triaxial compressive stress -strain curves were compared with the experimental results, and they present a good agreement with each other. The improved constitutive model can well re flect the nonlinear mechanical behavior of granite. (c) 2024 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting by Elsevier B.V. This is an open access article under the CC BY -NC -ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

Cement-based columns in combination with geosynthetic reinforcement is a well-established soft ground improvement technique to enhance embankment stability. This paper aims to present a finite-element (FE) study based on a case history of a geosynthetic-reinforced column-supported (GRCS) embankment over soft soil. In this study, the columns are simulated with an advanced Concrete model to simulate the development of possible cracking and induced strain-softening. Numerical results are compared against published centrifuge tests, giving confidence to the established FE model with the Concrete model. New insights into the progressive failure mechanisms of GRCS embankments over soft soil are then discussed by examining the stress paths, internal forces, and cracks, as well as the plastic failure zones of columns. In addition, the role of columns and geosynthetics on the progressive failure mechanisms (failure loads and sequences) is also examined by an extensive parametric study. The results suggest that provided the optimization of compressive and tensile forces in the columns combined with the tensile stiffness of the geosynthetics is put in place, more columns can be mobilized to resist global sliding failure and to improve the bearing capacity of GRCS embankments.