Analysis of the shear failure process of masonry by means of a meso-scopic mechanical modeling approach

2006 ◽  
Vol 24 (2) ◽  
pp. 181-194 ◽  
Author(s):  
Shuhong Wang ◽  
Chun'an Tang ◽  
Peng Jia
2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Chi Yao ◽  
Sizhi Zeng ◽  
Jianhua Yang

Anisotropy in strength and deformation of rock mass induced by bedding planes and interlayered structures is a vital problem in rock mechanics and rock engineering. The modified rigid block spring method (RBSM), initially proposed for modeling of isotropic rock, is extended to study the failure process of interlayered rocks under compression with different confining pressures. The modified rigid block spring method is used to simulate the initiation and propagation of microcracks. The Mohr–Coulomb criterion is employed to determine shear failure events and the tensile strength criterion for tensile failure events. Rock materials are replaced by an assembly of Voronoi-based polygonal blocks. To explicitly simulate structural planes and for automatic mesh generation, a multistep point insertion procedure is proposed. A typical experiment on interlayered rocks in literature is simulated using the proposed model. Effects of the orientation of bedding planes with regard to the loading direction on the failure mechanism and strength anisotropy are emphasized. Results indicate that the modified RBSM model succeeds in capturing main failure mechanisms and strength anisotropy induced by interlayered structures and different confining pressures.


2019 ◽  
Vol 16 (5) ◽  
pp. 862-874
Author(s):  
Yang Song ◽  
Heping Wang ◽  
Meng Ren

Abstract To study more fully the characteristic law of deformation and failure of tuff jointed rock mass of prefabricated parallel discontinuous joint test specimens, the uniaxial compression test was used. The stress–strain curve, peak intensity, deformation parameters, energy characteristics, etc., of the rock test specimens were systematically studied under different combinations of joint dip angle and joint spacing. The research found that: (1) during the failure process of tuff, the peak intensity and elastic modulus followed a U-shaped change pattern and the minimum value was reached when α = 60°; (2) the fracture modes of test specimens with different joint dip angles were different. When α = 30° and 45°, failure characteristics were mixed modes of tensile or tensile shear failure. When α = 60°, failure characteristics were shear. At α = 75°, the failure characteristic was tensile shear failure. (3) The absorbed and dissipated energy of the rock increased nonlinearly at each stage of deformation. (4) We quantified rock energy damage through a correlation between dissipated energy and absorbed energy of the rock in the process of energy evolution, and obtained an evolution of the relationship between the dissipated energy ratio, crack dip angle and crack spacing. Based on different fracture distribution methods and according to the strain equivalence principle, the constitutive equation of the pre-peak rock damage was obtained.


2019 ◽  
Vol 2019 ◽  
pp. 1-21
Author(s):  
Jun Xie ◽  
Yougang Yang

In order to analyze the torsional shear process of asphalt mixtures in a microscopic view, the numerical simulation of a torsional shear test of an asphalt mixture was carried out by discrete element method. Based on the defects of existing algorithms, the method of random reconstruction of the existing 3D model of the asphalt mixture was improved, and a new reconstruction method was proposed. A 3D numerical model of the asphalt mixture contained irregular-shaped coarse aggregate, mineral gradation, and asphalt mortar; furthermore, the particle algorithm established the air void distribution. Then, the numerical simulation of the asphalt mixture’s torsional shear was completed; in addition, the stress, displacement, and contact of the specimens at each stage were analyzed. The results showed that the stress and displacement in different stages changed greatly with the loading, i.e., the crack generated from a weak point on the surface and then spread to the ends with an oblique angle of about 45°. At the same time, the shear failure process of the asphalt mixture was studied. The virtual test method could accomplish the implementation of the numerical simulation of torsional shear; it also provided a good research method for analysis of the asphalt mixture’s shear failure process.


2011 ◽  
Vol 243-249 ◽  
pp. 3147-3150
Author(s):  
Shu Xian Liu ◽  
Xiao Gang Wei ◽  
Shu Hui Liu ◽  
Li Ping Lv

Disaster caused by exploiting underground coal is due to original mechanical equilibrium of underground rock has been destroyed when underground coal is exploited. And Stress redistribution and stress concentration of wall rock in the goaf happened too. As many complex factors exist such as complex structures of ground, multivariate stope boundary conditions, many stochastic mining factors and so on, it is difficult to evaluate the damage of the geological environment caused the excavation by surrounding underground coal accurately. Besides that, the coexistence of continuous and discontinuous of deformation and failure of wall rock make a strong impact on the ground, and the co-exist of tension, compression and shear failure also pay a great deal contribution to the destroy. Due to the mechanical property and deformation mechanism of goaf are complex , changeable, nonlinear and probabilistic, which changes with in space and time dynamically, it can not be studied analytically by the classical mathematical model and the theory of mechanics computation. Through finite element analysis software ABAQUS, a numerical simulation of the process of underground coal mining have been made. After make a research of the simulation process, it shows the change process of stress environment of wall rock and deformation and failure process of rock mass during the process of coal mining. The numerical simulation of the process can provide theoretical basis and technical support to the protection and reinforcement of laneway the process of coal excavation. Besides that, it also provides a scientific basis and has a great significance to reasonable Excavation and control of mind-out area.


2013 ◽  
Vol 351-352 ◽  
pp. 833-837
Author(s):  
Ji Liang Liu ◽  
Hui Chen Cui ◽  
Ming Jin Chu ◽  
Jian Qun Hou

The shear wall built with precast two-way hollow slab is an innovated precast concrete shear wall suitable for housing industrialization. Two shear walls built with precast two-way hollow slabs were tested pseudo-statically under low cyclic lateral loads to acquire their failure process and modes. The effect of the axial compression load was investigated. The study proved that vertical cracks along the vertical holes of the new type shear wall have been appeared to avoid brittle shear failure, and the shear wall developed integral section wall to walls-columns combination. As the results, the shear walls have the adequate deformability. The test results showed that with the increase of axial compressive ratio, crack development has been limited and the energy dissipation capacity has been improved. It also can be found that with the increase of the axial compressive load, shear capacity of the new type shear walls have been improved.


2013 ◽  
Vol 387 ◽  
pp. 189-192
Author(s):  
Feng Shan Han ◽  
Xin Li Wu

The geological storage of has been recognized as an important strategy to reduce emission in the atmosphere. Coal seam has strong absorption capacity for , hence the coal seam can be used as geological storage reservoirs, simple and easy to use modeling tools would be valuable in assessing the performance of deep underground geological storage. In this paper failure process of coal seam in deep underground under triaxial compressive experiment is presented by numerical simulation. That is of significance and valuable to those subjects of investigation of strength of coal seam in deep underground and mechanism of propagation and coalescence and evolvement of crack for coal seam in deep underground, it is shown by numerical simulation that failure shape of coal seam in deep underground under triaxial compressive experiment of lateral pressure of 25Mpa is typically shear failure, and characteristic of deformation is obviously elastic-brittle, which is significance to understand the performance of the coal seam in deep underground


2018 ◽  
Vol 134 ◽  
pp. 116-129 ◽  
Author(s):  
David Cereceda ◽  
Dmitriy Kats ◽  
Nitin Daphalapurkar ◽  
Lori Graham-Brady

Author(s):  
Ximei Zhai ◽  
Wenjian Ying ◽  
Wang Xueming

In order to ensure desirable overall performance between interior panel and exterior panel for precast concrete sandwich panels, the shear performance of a new composite connector is investigated in this paper through the experiment of shear specimens, including 4 groups of bilateral shear test specimens and 8 groups of unilateral shear test specimens. The connector’s shear capability and shear failure process phenomenon of destruction of all specimens are obtained. Then the effect rule on shear performance of connector from positional relation of connector and distribution reinforcement and concrete strength are gained. The experimental results and analysis show that the shear failure model is bending shear failure of connector’s reinforcing steel bar, which is brittle failure; the measured value of shear force of experiment compared to the measures values for the actual project, the new composite connector provides an enough safety reserve; The relative position of connector and distribution reinforcement and concrete strength have no influence on the ultimate bearing shear capability; The shear performance of the new composite connector could satisfy the use requirement of sandwich wall panels based on the text results. Furthermore, the connectors perform superb anchoring bond and deformation capability. According to the results and analysis, the new composite connector could be popularly used in engineering practice.


2011 ◽  
Vol 243-249 ◽  
pp. 573-577
Author(s):  
Hong Li ◽  
Shuang Gao ◽  
Tao Wu ◽  
Bo Quan Liu

On the basis of the experiment of 12 abnormal joints with different depth beams, failure process, seismic capacity and construction measure of this kind of joints are analyzed. Shear strength and failure model of joints with equivalent core height are analyzed by using mathematical model based on quadruple flexural resistance. The model satisfies equilibrium equations relating magnitude of external forces such as column shear, beam shear and axial force in column, to the magnitude of stress resultants. The results show that the model can reasonably explain the reasons for joints failure, have explicit mathematical model and good agreement between experimental results and calculated results of this model is achieved.


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