Failure analyses of unconfined CCWBM body in uniaxial compression based on central pressure variation

2018 ◽  
Vol 36 (2) ◽  
pp. 159-168 ◽  
Author(s):  
Xianjie Du ◽  
Guorui Feng ◽  
Yuxia Guo ◽  
Tingye Qi ◽  
Yujiang Zhang ◽  
...  
Keyword(s):  
Uniaxial Compression ◽  
Pressure Sensors ◽  
Cementitious Materials ◽  
Pressure Variation ◽  
Control Surface ◽  
Central Pressure ◽  
Coal Waste ◽  
Pressure Curve ◽  
Failure Characteristics ◽  
Backfill Mining

Cemented coal waste backfill material (CCWBM) is made of coal gangue, fly ash and cementitious materials. It has been widely used in the field of backfill mining to control surface subsidence and protect the environment. A large number of unconfined backfill bodies without lateral support are formed in partial backfill mining. To study the failure characteristics of unconfined CCWBM body in partial backfill, the stress–strain curves of the CCWBM were obtained by uniaxial compression tests at different ages (1–28 d). The central pressure was measured by the embedded pressure sensors. The failure characteristics of the specimen were monitored by acoustic emission (AE) positioning technique. Three observations can be made. 1. The central pressure variation curves lag behind the mean stress change curves. The central pressure curve can be divided into three stages: slow increase stage, rapid growth stage and decline stage. It has two pressure manifestations: early appearance and peak appearance. They can be as the failure precursor and instability critical, respectively. 2. The specimen forms a central elastic bearing area in the process of compression. The plastic area develops to the inner side with the increase of pressure, and an upper and lower compound cone-shaped residual area is finally formed. 3. The embedded pressure sensor can be used to monitor the instability of the unconfined backfill body. The research results can provide guidance for the in-situ stability monitoring and reinforcement of unconfined CCWBM body in partial backfill.

Research on the macro-meso failure characteristics of single jointed granite under uniaxial compression

2022 ◽  
Vol 15 (1) ◽  
Author(s):  
Lichao Zhou ◽  
Gang Wang ◽  
Leibo Song ◽  
Wenzhao Chen ◽  
Hongxia Lei
Keyword(s):  
Uniaxial Compression ◽  
Failure Characteristics

Experimental study and numerical simulation of uniaxial compression on artificial rock samples with Z-shaped fractures

2021 ◽  
Author(s):  
Tao Zhou ◽  
Haijun Chen ◽  
Liangxiao Xiong ◽  
Zhongyuan Xu ◽  
Jie Yang ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Crack Length ◽  
Uniaxial Compression ◽  
Inclination Angle ◽  
Failure Surface ◽  
Peak Strength ◽  
Particle Flow Code ◽  
Compression Tests ◽  
Failure Characteristics ◽  
Change Trend

Abstract To study the influence of the inclination and length of Z-shaped fissures on the mechanical properties and failure characteristics of the rock mass, this study conducts a series of uniaxial compression tests on rock-like materials with prefabricated Z-shaped fractures. In addition, two-dimensional Particle Flow Code software is used to perform uniaxial compression numerical simulations. The results show that when the specified inclination angle γ (γ = 0°, 30° or 45°) of the parallel cracks on both sides remains unchanged, the peak strength and elastic modulus of the sample show an M-shaped change trend with an increase in the inclination angle β of the middle connection crack. When γ = 60° or 90°, however, the peak strength and elastic modulus of the sample show a trend of decreasing, increasing, and then decreasing as β increases. In addition, the peak strength and elastic modulus of the sample decrease with an increase in the crack length. The influence of crack length on the elastic modulus is less than that of compressive strength. Further, the main failure mode of specimens with Z-shaped cracks is determined to be tension–shear mixed failure manifested by crack propagation from the tip of the prefabricated crack to the upper and lower boundaries of the sample. As a result, a through failure surface is formed with the prefabricated crack, which destroys the sample.

scholarly journals Deformation and failure characteristics of weathered granite under uniaxial compression

AIP Advances ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 075222 ◽  
Author(s):  
Lingfan Zhang ◽  
Duoxing Yang ◽  
Zhonghui Chen
Keyword(s):  
Uniaxial Compression ◽  
Failure Characteristics ◽  
Deformation And Failure ◽  
Weathered Granite

Flow control with active dimples

2007 ◽  
Vol 111 (1125) ◽  
pp. 705-714 ◽  
Author(s):  
S. Dearing ◽  
S. Lambert ◽  
J. Morrison
Keyword(s):  
Pressure Sensors ◽  
Fast Response ◽  
Vortex Generators ◽  
Control Surface ◽  
Real Time Control ◽  
Capacitance Change ◽  
Time Control ◽  
Design And Manufacture ◽  
Smart Skin

Abstract The long-term goal is to design and manufacture optimal ‘on-demand’ vortex generators, ‘dimples’ that can produce vortices of prescribed strength and duration for the real-time control of aerodynamic flows that are either undergoing transition or are fully turbulent, attached or separating. Electro-active polymers (EAP) are ideal for a dimple control surface, offering high strain rate, fast response, and high electromechanical efficiency. EAP can also be used as the basis of a resistanc – or capacitance – change pressure sensor, development of which has just begun. In terms of manufacture, inkjet printing of EAP also offers a paradigm shift such that a monolithic control surface is a very real possibility. Important features for integration into a control system are robustness and a predictable, repeatable motion. With these objectives in mind, the suitability of EAP-based actuators is assessed both mechanically and aerodynamically. The ultimate goal is to integrate these devices, along with shear-stress and pressure sensors and distributed control, also under development, into a flexible ‘smart skin’ which could be incorporated into an airframe structure. The response of a laminar boundary layer to forcing is investiagted using mechanical dimples.

Experimental Study on Performance of Pressure Sensor and Similar Material Model

2010 ◽  
Vol 163-167 ◽  
pp. 4537-4541
Author(s):  
Shao Jie Chen ◽  
Bo Li ◽  
Wei Jia Guo
Keyword(s):  
Mechanical Properties ◽  
Pressure Sensor ◽  
Pressure Sensors ◽  
Material Model ◽  
Repeated Loading ◽  
Pressure Curve ◽  
Test Results ◽  
Similar Material ◽  
Matching Problem ◽  
Similar Materials

In this paper, in order to get the mechanical properties of the different ratio similar material models and resolve the matching problem of pressure sensor and measured similar material, according to the similarity theories, the repeated loading tests on different ratio similar models were performed by multi-stage loading. This paper got the stress-pressure curve and the failure strength of each model. Test results show that there are significant differences in the matching abilities between different ratio similar materials and pressure sensors, and the matching abilities between different models of the same ratio and pressure sensors also have some differences. The matching ability between similar material and pressure sensor should be detected, so as to correct the experimental data. Test results also show that different ratio similar materials have stable and different mechanical properties. The mechanical properties of the similar material can be adjusted appropriately by changing the ratio. The mechanical properties of different ratio similar materials should be tested before the similar material simulation test.

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