Direct shear behavior of a plane joint under dynamic normal load (DNL) conditions

Dang, Wengang; Konietzky, Heinz; Frühwirt, Thomas

doi:10.1016/j.enggeo.2016.08.016

Cited by 66 publications

(12 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the two lower wings became the macroscopic rupture boundary. According to the research [24][25][26][27], the stress region of both the postexcavation coal mine roadway and the loaded specimen is divided into the elastic zone and plastic zone with ring-shaped distribution and other zone, and thus, the first response time of the strain measurement point is presented ring-shaped distribution basically. As the load on the specimen increases, the radius of plastic area continues to expand, which provides a channel for crack extending.…”

Section: Relationship Between Initial Strain Time and Finalmentioning

confidence: 99%

Physical Simulation and Monitoring the Deformation and Fracture of Roadway in Coal Mining

Liu

Yang

Ding

et al. 2018

Advances in Civil Engineering

View full text Add to dashboard Cite

Aiming at the large deformation and the dynamic fracture of roadway during the underground excavation or mining, a physical simulation and strain testing system was established, and the deformation process of surrounding body and its inner strain characteristics of the simulated roadway under loading was carried out. Results showed that the inner strain change of the measurement points can be divided into three types: the strain firstly increases and then decreases, the strain slowly increases and then increases sharply, and strain firstly reduces and then increases. The strain starting time is closely related to the failure path and boundary of tested samples. This paper suggested two criteria for determining the instability of roadways, which are a huge and faster increase of strain at the location of the roof and floor with high absolute value, or a small increase with a peak value or irregular fluctuation. This paper provides a new idea for the simulation of roadway instability and is significant in deeper understanding the deformation and destabilization of underground roadway.

show abstract

Section: Relationship Between Initial Strain Time and Finalmentioning

confidence: 99%

Physical Simulation and Monitoring the Deformation and Fracture of Roadway in Coal Mining

Liu

Yang

Ding

et al. 2018

Advances in Civil Engineering

View full text Add to dashboard Cite

show abstract

“…It is difficult to simulate the engineering disturbance environment and complex boundary conditions of deep rock mass. [22][23][24] Discrete element numerical method of particle flow is an effective method to study the complex fracture mechanical behavior of rock. It separates rock-like materials into rigid particle aggregates and bonding matrix, and studies the fracture mechanism of rock-like media from a mesoscopic perspective.…”

Section: Introductionmentioning

confidence: 99%

“…However, due to the limitation of test conditions, the existing dynamic shear test device is mainly to explore the shear rate and cyclic shear action. It is difficult to simulate the engineering disturbance environment and complex boundary conditions of deep rock mass 22–24 …”

Section: Introductionmentioning

confidence: 99%

Investigations on the macro‐meso mechanical properties and energy dissipation mechanism of granite shear fracture under dynamic disturbance

Wang

Luo

Gong

et al. 2023

Num Anal Meth Geomechanics

View full text Add to dashboard Cite

To explore the mechanical characteristics and failure mechanisms of rock shear fracture under dynamic disturbance, the laboratory shear test and numerical simulation based on particle flow code (PFC) were carried out, and the mesoscopic degradation characteristics and energy dissipation mechanisms of rock shear fracture were analyzed. The results show that: (1) The crack initiation stress of rock under the disturbance condition is relatively reduced by 20%–29%, and there is a “shear fracture weakening effect.” The frequent alternating effect of stress concentration and release at the post‐peak failure stage is more obvious. (2) The number of cracks in rock under shear action shows the evolution of “calm → low speed growth → rapid increase → decrease of amplification → stabilization” with the increase of shear displacement. Compared with the conventional shear test, more cracks, and wider debris zones are formed. The number of cracks increases by 53%–106%, and the number of debris increases by 31%–138%. (3) The energy change trend of disturbance shear fracture test is basically consistent with that of conventional shear test. With the increase of normal stress, the input energy, elastic strain energy and dissipation energy of rock failure point show a certain linear growth feature. Compared with the conventional shear test, the input energy and stored strain energy of the failure point in the disturbance shear test are smaller, with relative reduction of 16.5% and 22.1%. Namely, the normal frequent disturbance reduces the energy storage capacity and failure resistance of rock.

show abstract

“…The existing rock material direct shear test studies were conducted mainly under constant normal loads, while relevant studies using dynamic normal loads are fewer. Dang [ 26 , 27 ] studied the mechanical properties of planar joints under dynamic normal load (DNL) with different frequencies and amplitudes with the GS-1000 shear box device. However, the existing rock mechanics or rock dynamics can not be directly used to explain the shear mechanical properties under disturbance.…”

Section: Introductionmentioning

confidence: 99%

Mechanical and Acoustic Emission Characteristics of Coal-like Rock Specimens under Static Direct Shear and Dynamic Normal Load

Guo

Wen

et al. 2022

Materials

View full text Add to dashboard Cite

In underground engineering, shear failure is a common failure type in coal-rock mass under medium and low strain-rate disturbance loads. Analyzing the shear failure mechanical properties of coal-rock mass under dynamic normal load is significant. In order to reveal the influence of disturbance load on the shear mechanical properties of coal rock, a dynamic and static load coupling electro-hydraulic servo testing machine was used to conduct the shear tests of coal-like rock materials under dynamic and constant normal load. The amplitude of dynamic load is 10 kN and the frequency is 5 Hz. The damage process of the specimens was detected by the acoustic emission (AE) detection system. The results imply that the shear failure process of coal-like rock materials under constant normal load can be divided into four stages. The normal disturbance decreased the shear strength of the specimens and increased the shear modulus of the specimens. With the increase in normal load, the influence of disturbance on the shear strength of the specimen decreased. By analyzing the AE parameters, it was found that the dynamic load made the internal damage of the specimen more severe during the shear failure process. The damage variable was calculated by AE cumulative energy, and the damage evolution was divided into three stages. The shear failure mechanism of the specimen was judged by RA (rise time/amplitude) and AF (average frequency). It was found that from the elastic deformation stage to the unstable development fracture stage, the proportion of shear fracture increased. When the dynamic normal load was 10 kN and 30 kN, the fracture was mainly shear fracture; When the dynamic normal load was 50 kN, the fracture was mainly tensile or mixed fracture. The dynamic normal load affects the shear strength and failure mechanism. Therefore, the influence of disturbance load on coal-rock mass strength cannot be ignored in underground engineering.

show abstract

Direct shear behavior of a plane joint under dynamic normal load (DNL) conditions

Cited by 66 publications

References 26 publications

Physical Simulation and Monitoring the Deformation and Fracture of Roadway in Coal Mining

Physical Simulation and Monitoring the Deformation and Fracture of Roadway in Coal Mining

Investigations on the macro‐meso mechanical properties and energy dissipation mechanism of granite shear fracture under dynamic disturbance

Mechanical and Acoustic Emission Characteristics of Coal-like Rock Specimens under Static Direct Shear and Dynamic Normal Load

Contact Info

Product

Resources

About