scholarly journals Floor Heave Mechanism and Anti-Slide Piles Control Technology in Deep and Large-Span Chamber

2021 ◽  
Vol 11 (10) ◽  
pp. 4576
Author(s):  
Jian Shi ◽  
Desen Kong
Keyword(s):  
Model Test ◽  
Shear Failure ◽  
Deformation Mode ◽  
Control Technology ◽  
Plastic Limit ◽  
Large Span ◽  
Similarity Model ◽  
Floor Heave ◽  
Plastic Limit Analysis ◽  
Local Shear

Based on plastic limit analysis, the deformation and fracture mechanism of the floor in the large-span chambers of deep mines are discussed and a similarity model test is carried out to verify the reliability of the theoretical analysis. The results show that the local shear failure first appears below the loading area and develops to the middle part of the test model with the increase in load; when the local shear failure develops to form a continuous sliding surface, continuous plastic flow deformation occurs; the distribution of the plastic zone and the deformation mode obtained from the similarity model test are basically consistent with the Hill-like deformation mode derived from plastic limit analysis. A control technology with anti-slide piles is proposed in order to deal with floor heave in large-span chambers on the basis of previous work. An approach for determining the supporting parameters of anti-slide piles is deduced. To deal with the floor heave in the −1100 level gangue winch room of the Huafeng Coal Mine, a comprehensive reinforcement scheme with anti-slide piles composed of discarded rails and anti-floating anchors is introduced for the floor heave control of the chambers. Site monitoring results show that the scheme not only effectively restrains the development of floor heave, but also ensures the long-term stability of the chamber floor.

Model Test on Incremental Launching Construction Method for JIUBAO Bridge in Hangzhou

2013 ◽  
Vol 689 ◽  
pp. 389-393
Author(s):  
Bing Jie Li
Keyword(s):  
Model Test ◽  
Construction Method ◽  
Test Method ◽  
Dead Load ◽  
The Real ◽  
Large Span ◽  
Additional Weight ◽  
Similarity Model ◽  
Late Model ◽  
Test Result

The incremental launching construction method of super large-span arch-girder combination bridges is a new way in construction for late-model bridges. In order to study the dangerous conditions during the construction of the real bridge, the similarity model of a large-span arch-girder combination bridge is introduced. This article discussed structure responses under one，two，three times dead-load additional weight and the wind load separately. The test result demonstrates that the test method could simulate the dangerous conditions during the real construction and check the stress effectively which can provide technical support for the construction of similar bridges.

Plastic limit analysis with non linear kinematic strain hardening for metalworking processes applications

2011 ◽  
Vol 25 (11) ◽  
pp. 2859-2870 ◽  
Author(s):  
Ali Chaaba ◽  
Lahbib Bousshine ◽  
Mohamed Aboussaleh ◽  
Hassan El Boudaia
Keyword(s):  
Strain Hardening ◽  
Limit Analysis ◽  
Plastic Limit ◽  
Non Linear ◽  
Plastic Limit Analysis

Dimensional Design on the Six-Cable Driven Parallel Manipulator of FAST

2011 ◽  
Vol 133 (11) ◽  
Author(s):  
Xiaoqiang Tang ◽  
Rui Yao
Keyword(s):  
Radio Telescope ◽  
Parallel Manipulator ◽  
Optimization Design ◽  
Design Method ◽  
Guizhou Province ◽  
Large Span ◽  
Similarity Model ◽  
Dimensional Parameters ◽  
Set Up ◽  
Design Result

China is now building the world’s largest single dish radio telescope in Guizhou province, which is called Five-hundred meter Aperture Spherical radio Telescope (FAST). The main purpose of this paper is to present an effective dimensional design method on the six-cable driven parallel manipulator of FAST. Sensitivity design method is adopted for the six-cable driven parallel manipulator of FAST. Cable has the capability to bear tension but not compression, so that cable driven parallel manipulator may not be controlled as expected if tension of one cable is small or zero. Therefore, for dimensional design of the six-cable driven parallel manipulator, three functions to evaluate tension performance were proposed. The tension performance functions can reflect the uniformity of cable tension and controllability of the six-cable driven parallel manipulator. According to the sensitivity design method and tension performance evaluating functions, a set of optimized dimensional parameters is calculated for constructing the six-cable driven parallel manipulator of FAST. In order to verify the optimization design result, a similarity model of the six-cable driven parallel manipulator was set up in Beijing. A serial of experiments shows that tension performance of the six-cable driven parallel manipulator satisfies the system’s requirement. More importantly, it provides a theoretical reference for further study on dimensional design of a cable driven parallel manipulator with large span.

A numerical approach to predict soil bearing potential for isolated footing

2021 ◽  
Author(s):  
Gilbert Hinge ◽  
Jayanta Kumar Das ◽  
Biswadeep Bharali
Keyword(s):  
Bearing Capacity ◽  
Shear Failure ◽  
Correlation Coefficients ◽  
Failure Criteria ◽  
Numerical Approach ◽  
Ultimate Bearing Capacity ◽  
Foundation Design ◽  
Advantages And Disadvantages ◽  
Local Shear ◽  
Failure Conditions

<p>The success of any civil engineering structure's foundation design depends upon the accuracy of estimation of soil’s ultimate bearing capacity. Numerous numerical approaches have been proposed to estimate the foundation's bearing capacity value to avoid repetitive and expensive experimental work. All these models have their advantages and disadvantages. In this study, we compiled all the governing equations mentioned in Bureau of Indian standard IS:6403-1981 and modify the equation for Ultimate Bearing Capacity. The equation was modified by considering two new parameters, K1(for general shear) and K2 (for local shear) so that a common governing equation can be used for both general and local shear failure criteria. The program used for running the model was written in MATLAB language code and verified with the observed field data. Results indicate that the proposed model accurately characterized the ultimate, safe, and allowable bearing capacity of a shallow footing at different depths. The correlation coefficients between the observed and model-predicted bearing capacity values for a 2m foundation depth with footing size of 1.5 ×1.5, 2.0 × 2.0, and 2.5 × 2.5 m are 0.95, 0.94, and 0.96. A similar result was noted for the other foundation depth and footing size. Findings show that the model can be used as a reliable tool for predicting the bearing capacity of shallow foundations at any given depth.  Moreover, the formulated model can also be used for the transition zone between general and local shear failure conditions.</p>

scholarly journals Reliability Based Analysis and Optimum Design of Laterally Loaded Piles

2017 ◽  
Author(s):  
Majid Movahedi Rad
Keyword(s):  
Limit Analysis ◽  
Strain Energy ◽  
Load Capacity ◽  
Optimization Procedure ◽  
Load Parameter ◽  
Plastic Limit ◽  
Laterally Loaded Piles ◽  
Plastic Limit Analysis ◽  
Complementary Strain ◽  
Laterally Loaded

In this study reliability based limit analysis is used to determine the ultimate capacity of laterally loaded piles.  The aim of this study is to evaluate the lateral load capacity of free-head and fixed-head long pile when plastic limit analysis is considered. In addition to the plastic limit analysis to control the plastic behaviour of the structure, uncertain bound on the complementary strain energy of the residual forces is also applied. This bound has significant effect for the load parameter. The solution to reliability-based problems is based on a direct integration technique and the uncertainties are assumed to follow Gaussian distribution. The optimization procedure is governed by the reliability index calculation.

scholarly journals Failure Characteristics and Mechanism of Multiface Slopes under Earthquake Load Based on PFC Method

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Tao Yang ◽  
Yunkang Rao ◽  
Huailin Chen ◽  
Bing Yang ◽  
Jiangrong Hou ◽  
...  
Keyword(s):  
Moisture Content ◽  
Failure Mechanism ◽  
Failure Modes ◽  
Shear Failure ◽  
Shaking Table ◽  
Tensile Failure ◽  
Particle Flow Code ◽  
Shear Cracks ◽  
Local Shear ◽  
Shear Slip

Understanding the failure mechanism and failure modes of multiface slopes in the Wenchuan earthquake can provide a scientific guideline for the slope seismic design. In this paper, the two-dimensional particle flow code (PFC2D) and shaking table tests are used to study the failure mechanism of multiface slopes. The results show that the failure modes of slopes with different moisture content are different under seismic loads. The failure modes of slopes with the moisture content of 5%, 8%, and 12% are shattering-shallow slip, tension-shear slip, and shattering-collapse slip, respectively. The failure mechanism of slopes with different water content is different. In the initial stage of vibration, the slope with 5% moisture content produces tensile cracks on the upper surface of the slope; local shear slip occurs at the foot of the slope and develops rapidly; however, a tensile failure finally occurs. In the slope with 8% moisture content, local shear cracks first develop and then are connected into the slip plane, leading to the formation of the unstable slope. A fracture network first forms in the slope with 12% moisture content under the shear action; uneven dislocation then occurs in the slope during vibration; the whole instability failure finally occurs. In the case of low moisture content, the tensile crack plays a leading role in the failure of the slope. But the influence of shear failure becomes greater with the increase of the moisture content.

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