Institute of Engineering Corps

Tongshan, China

Institute of Engineering Corps

Tongshan, China

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Han J.,Shandong University of Finance and Economics | Han J.,Shandong University | Li S.,Shandong University | Wang L.,Shandong University | And 3 more authors.
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | Year: 2013

Based on the mechanical behavior that the strength parameters evolve with the increase of major principal plastic strain, the method of solving nonlinear express of strain softening curve of rock mass was proposed by theoretical derivation by using the generalized Hoek-Brown (H-B) strength criterion and choosing the major principal plastic strain as strain softening parameter, on the assumption that the strength parameters m, s and a in generalized Hoek-Brown strength criterion can be described by bilinear function of the major principal plastic strain. Finally, in numerical case, the influence of evolutional law of strength parameters m, s and a on strain softening behavior was discussed. The results show that the larger the residual values of m, s and the smaller the residual value of a, the post-failure strain softening curve falls more gently and the larger the residual strength is.


Tong X.,Shandong University | Han J.,Shandong University | Han J.,Shandong University of Finance and Economics | Li S.,Shandong University | And 2 more authors.
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | Year: 2013

Based on the evolution of post-peak strength parameters, using Mohr-Coulomb strength criterion, regarding maximum principal strain of rock and shear displacement of crack as softening parameter, the method of solving relation of post-peak stress-strain of rock and relation of post-peak stress-displacement was presented respectively on the assumption that the strength parameter is a piecewise linear function of softening parameters. Then the method to solve post-peak stress-strain relation of rock mass with stochastic distribution of penetrative cracks was obtained by probability approach. Finally the effect of mean space, normal stiffness and shear stiffness of cracks to post-peak strain was discussed using an example. The example result shows that the smaller the mean space, normal stiffness and shear stiffness of cracks are, the larger the strain of fractured rock mass is.


Li S.,Shandong University | Wang L.,Shandong University | Wang L.,Institute of Engineering Corps | Han J.,Shandong University | Han J.,Shandong University of Finance and Economics
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering | Year: 2013

The uniaxial compression test of pre-existing persistent jointed rock-like specimens is carried out by high stiffness servo control testing machine. Systematic researches on the relationship of post-peak stress-strain curve, failure form, strength after peak, the Poisson's ratio after peak of rock masses with dip angles of persistent joints are performed. The results indicate that: (1) The post-peak stress-strain curves of specimens with joint inclination angle of 15° and complete specimens are basically the same, but the post-peak stress-strain curves of specimens with the joint inclination angle of 30°, 40°, 50° to 60° and complete specimens vary greatly. (2) Peak strength decreases with the increase of joint inclination angle, residual post-peak strength also generally increases as the joint angle increases. (3) Poisson's ratio of jointed specimen increases with joint inclination angle increases, but the post-peak visual Poisson's ratio becomes smaller in the phase of destruction with joint inclination angle increases. (4) The post-peak failure modes of specimen change with joint inclination angle. Specimens damage is splitting failure at the joint inclination angle of 15°, shear failure at the joint inclination angle of 50° and 60°, splitting and shear mixing model at the joint inclination angle of 30° and 40°. The research result can reflect mechanics, deformation and damage characteristics under uniaxial compressive loading in the phase of post-peak of rock masses with different dip angles pre-existing persistent joints.


Hao S.,Engineering Research and Design Institute of Jinan Military Region | Zhang Y.,Institute of Engineering Corps | Wang Y.,Engineering Research and Design Institute of Jinan Military Region | Shangguan L.,Engineering Research and Design Institute of Jinan Military Region | And 3 more authors.
Hecheng Shuzhi Ji Suliao/China Synthetic Resin and Plastics | Year: 2014

The authors prepared the epoxy resin/nano-SiO2 composite and studied the effects of nano-SiO2 dosage on its structure and mechanical properties. The fracture morphology of the epoxy resin/nano-SiO2 composite was observed by means of scanning electron microscope(SEM) and the toughening mechanism of nano-SiO2 was analyzed. The mechanical properties of the epoxy resin could be enhanced remarkably by adding appropriate amount of nano-SiO2. The mechanical properties of the epoxy resin/nano-SiO2 composite were the best when the content of nano-SiO2 was 6 phr. The tensile shear strength, flexural strength, Izod notched impact strength were 13.8 MPa, 86.1 MPa, 11.6 kJ/m2 respectively. Adding appropriate amount of nano-SiO2 could improve the internal structure of the composites and the nano-SiO2 had signally toughening and reinforcement effect on the composites.


Han J.,Shandong University | Han J.,Shandong University of Finance and Economics | Tong X.,Shandong University | Wang L.,Shandong University | And 3 more authors.
Applied Mechanics and Materials | Year: 2012

In order to predict the stability of surrounding rock mass in geotechnical engineering, it is important to study the post-failure deformation property and residual strength of rock mass. Based on evolutional behavior of strength parameters, aiming at generalized Hoek-Brown strength criterion, selecting major principal strain ε1 as strain softening parameter, this paper presents the method of solving post-failure stress-strain curve. In numerical case, the effect of evolutional law of strength parametersm, s and a to deformation and residual strength is discussed and we can draw the following conclusions: the greater the residual values of m, s are and the smaller the residual value of a is, the post-failure strain softening curve falls more gently and the greater the residual strength is. © (2012) Trans Tech Publications, Switzerland.


Han J.-X.,Shandong University of Finance and Economics | Han J.-X.,Shandong University | Li S.-C.,Shandong University | Yang W.-M.,Shandong University | And 2 more authors.
Yantu Lixue/Rock and Soil Mechanics | Year: 2013

The post-peak deformational characteristics of rock materials play a leading role in safety of geotechnical engineering. So it is important to study the post-peak stress-strain relationship. Based on the evolution of post-peak strength parameters of rock material, a general method for establishing the stress-strain relationship is presented. Firstly, strength criterion is selected to establish the connection of stress with strength parameters. Then, the relationship between strength parameters and strain softening parameter is determined. Finally, the post-peak stress-strain relationship can be obtained by strength parameters which are as intermediate variables. On this basis, based on Mohr-Coulomb strength criterion, regarding maximum principal strain ε1 as strain softening parameter, on the assumption that the cohesion c and friction angle φ are the piecewise linear functions of ε1, the method of solving express of post-peak stress-strain relationship is obtained. In numerical cases, the stress-strain curves under different confining pressures are obtained and they agree well with the test data. It reveals that the method proposed by this paper is reasonable and effective in studying post-peak stress-strain relationship.

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