scholarly journals Experimental Study of an Inflatable Recyclable Anchor

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Taoli Xiao ◽  
Yunlong He
Keyword(s):  
Bearing Capacity ◽  
Embedment Depth ◽  
The Novel ◽  
Low Carbon ◽  
Pullout Capacity ◽  
Force Transmission ◽  
Inflation Pressure ◽  
Foundation Pit ◽  
Anchor System ◽  
Repeated Use

This paper describes an investigation into the performance and pullout capacity of a new inflatable anchor system embedded in deep excavation engineering. The proposed inflatable recyclable anchor system consists of a rubber pneumatic bag, movable steel plate, and force transmission bar, which can all be recycled after use. By conducting a number of field pullout tests, it is found that the pullout bearing capacity of the proposed anchor is related to the inflation pressure, the length of the rubber pneumatic bag, and the embedment depth. It is found that, with the exponential increase of inflation pressure or length of the rubber pneumatic bag, the pullout bearing capacity of the novel inflatable anchor increases exponentially. The proposed inflatable recyclable anchor can meet the bearing requirements of traditional grouted anchors. Moreover, the proposed anchor not only has better supporting effects than traditional grouted ones, but it also has the advantages of recyclability, repeated use, and rapid formation of anchorage force. It is a new green and low-carbon anchorage, so it will have good application prospects in temporary foundation pit slope engineering.

scholarly journals Experimental and Numerical Studies on the Inflatable Recyclable Anchor in the Tube Piece Type Based on the Soil-Anchor Interaction Mechanism

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Chenchen Du ◽  
Taoli Xiao ◽  
Yunlong He ◽  
Xuexiang Yang
Keyword(s):  
Bearing Capacity ◽  
Interaction Mechanism ◽  
The Novel ◽  
Inflation Pressure ◽  
Analysis Model ◽  
Distribution Law ◽  
Resource Saving ◽  
Element Analysis ◽  
Steel Disc ◽  
Embedment Length

This paper deeply studies the characteristics and “uplift bearing capacity” of a novel type of inflatable recyclable anchor in the tube piece. The proposed novel inflatable recyclable anchor in the tube piece type comprises a metallic rod, an inflatable anchorage device, and a recovery device. Fifteen field uplift tests are conducted to investigate the effects of inflation pressure, thickness of the steel disc, embedment length, and time lapse between anchor inflation and pullout on “the uplift bearing capacity.” The results show that “the uplift bearing capacity” of the novel inflatable anchor in the tube piece type increases with the increase of inflation pressure, thickness of the steel disc, and embedment length. With the increase of inflation time, “the uplift bearing capacity” of the novel inflatable anchor experiences an increase after first experiencing a decrease. The finite element analysis method is used to establish a numerical analysis model of the inflatable anchor, and the distribution law of the tensile stress of the surrounding soil during the pullout of the anchor is analysed. Compared with the traditional grouted anchor, the proposed anchor has an obvious superiority in recyclability, reusability, and swifter formation of anchorage force and thus is a resource-saving and environmentally friendly anchor technology.

scholarly journals Development of a New Inflatable Controlled Anchor System and Experimental Study of pull-out Capacity

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Xuexiang Yang ◽  
Shanpo Jia ◽  
Caoxuan Wen ◽  
Yuanjie Liu
Keyword(s):  
Bearing Capacity ◽  
Field Tests ◽  
Ultimate Bearing Capacity ◽  
Inflation Pressure ◽  
Working Mechanism ◽  
Anchor System ◽  
System A ◽  
Pull Out ◽  
New Type ◽  
Soil Interface

Considering the deficiency of traditional anchors, we propose a new type of inflatable controlled anchor system in this paper. The working mechanism and its structural composition of newly designed inflatable controlled device are discussed in detail. To investigate the performance and pull-out capacity of this new anchor system, a series of field tests were carried out under different inflation pressure conditions. By comparing these test results with those of traditional grouting anchors, a full-process constitutive model of anchor-soil interface is proposed to depict the pull-out characteristics of the inflatable controlled anchor. The results show that the ultimate bearing capacity of the inflatable controlled anchor is greater than that of the traditional grouting anchor when the inflation pressure is greater than 0.2 MPa and the ultimate bearing capacity of this new anchor improves obviously with the increase of inflation pressure. When the inflation pressure reaches 0.4 MPa, the ultimate bearing capacity of the inflatable controlled anchor is 2.08 times that of the traditional grouting anchor. Through comparison with the experimental curves, the results of model calculation indicate that the proposed anchor-soil interface constitutive equation can describe the pull-out characteristics of the inflatable controlled anchor. The designed controlled anchor has the advantages of no grouting, recyclability, rapid formation of anchoring force, and adjustable anchoring force.

scholarly journals Behavior of bladder-type inflatable anchors in sand: Physical modeling

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110151
Author(s):  
Wang Lichang ◽  
Xu Meng ◽  
Peng Wenxiang ◽  
Long Wei ◽  
Shou Keh-Jian ◽  
...  
Keyword(s):  
Film Thickness ◽  
Test Chamber ◽  
Primary Objective ◽  
Embedment Depth ◽  
Inflation Pressure ◽  
Foundation Pit ◽  
Pull Out ◽  
The Impact ◽  
Rubber Film ◽  
Ultimate Displacement

This paper describes an investigation into the performance and pull-out capacity of a bladder-type inflatable anchor. The inflatable anchor is a type of support member used in foundation pit support engineering. Based on improvements and innovations, the multi-bladder-type inflatable anchor consists of two or more hydraulically inflated rubber membranes that are embedded in unconsolidated earth and then inflated to provide pull-out capacity. The primary objective of this study was to investigate the impact of inflation pressure, embedment depth, number of bladders, bladder length, and rubber film thickness on the pull-out capacity and displacement of the inflatable anchor. The tests were carried out in a cylindrical steel test chamber filled with medium coarse sand. The pull-out behavior of the bladder-type inflatable anchor and the five variables was investigated, and the benchmark values for all tests are determined by similarity ratio. Compared with the single bladder inflatable anchor, under the same conditions, the ultimate pull-out capacity of the two bladder-type inflatable anchor is 1.2 times higher, with ultimate displacement only 37.5% of the former, the ultimate pull-out capacity of the three bladder-type inflatable anchor is 1.7 times higher, with ultimate displacement only 32.3% of the former. The two bladder-type inflatable anchor is superior to the single bladder inflatable anchor and the multi-bladder-type has higher ultimate pull-out capacity and greater stiffness. The inflation pressure and the rubber film thickness have a significant influence on the bearing capacity. The number of bladders effectively controls the ultimate displacement.

scholarly journals Experiment Investigation on Stress Characteristics of Grouting Microsteel Pipe Piles with Cement-Soil Wall

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Shujuan Yang ◽  
Mingyi Zhang ◽  
Xiaoyu Bai ◽  
Xueying Liu ◽  
Chen Zheng
Keyword(s):  
Bearing Capacity ◽  
Stress Measurement ◽  
Flexural Rigidity ◽  
Bending Moment ◽  
Steel Tube ◽  
Rock Foundation ◽  
Foundation Pit ◽  
Anchor System ◽  
In Situ Stress Measurement ◽  
Cement Soil

Microsteel pipe piles are widely used in excavation support owing to their excellent bearing capacity, flexural rigidity, construction speed, and adaptability. In this study based on a project in soil-rock layers in Qingdao, China, a new type of support combining microsteel pipe piles mounted in cement-soil piles and anchors was adopted and studied. The inner force change laws and bearing capacity of microsteel pipe piles were discussed through in situ stress measurement and laboratory antibending tests on three microsteel pipe piles. It was found that the bending moment of the piles gradually increased with the foundation excavation and maximized at the pile head. The bending moment was larger at the upper and smaller at the lower part along the depth direction, indicating it is reasonable to design and calculate microsteel pipe piles by the pile-anchor system. The variation law of the foundation pit displacement with the excavation depth was monitored. The horizontal displacement of the foundation pit is the maximum at the base top, which is 6.5 mm. The flexural strength of the miniature steel tube pile after grouting is 40% higher than that of the miniature steel tube pile without grouting. It was indicated that the grouting microsteel pipe piles could be implanted in cement-soil piles, which improved the flexural rigidity of cement-soil piles and limited the deformation of foundation pits. This study provides reference for the design and construction of soil-rock foundation pit supporting projects. At the same time, it provides reference for the application of miniature steel pipe piles in other fields.

scholarly journals 3-D Numerical Study of Mechanical Behaviors of Pile-Anchor System

2014 ◽  
Vol 580-583 ◽  
pp. 238-242
Author(s):  
Ri Cheng Liu ◽  
Bang Shu Xu ◽  
Bo Li ◽  
Yu Jing Jiang
Keyword(s):  
Simulation Analysis ◽  
Numerical Study ◽  
Bending Moments ◽  
Mechanical Behaviors ◽  
Foundation Pit ◽  
Anchor System ◽  
Anchor Cable ◽  
Axial Forces ◽  
Toppling Failure ◽  
Potential Failure

Mechanical behaviors of pile-soil effect and anchor-soil effect are significantly important in supporting engineering activities of foundation pit. In this paper, finite difference method (FDM) was utilized to perform the numerical simulation of pile-anchor system, composed of supporting piles and pre-stressed anchor cables. Numerical simulations were on the basis of the foundation pit of Jinan’s West Railway Station, and 3D simulation analysis of foundation pit has been prepared during the whole processes of excavation, supporting and construction. The paper also analyzed the changes of bending moments of piles and axial forces of cables, and discussed mechanical behaviors of pile-anchor system, through comparisons with field monitoring. The results show that the parameters concluding vertical gridding’s number, cohesion of pile and soil, and pile stiffness have robust influences on supporting elements’ behaviors. Mechanical behaviors of supporting pile and axial forces of anchor cable changed dramatically, indicating that the potential failure form was converted from toppling failure to sliding failure.

scholarly journals Three-dimensional observations of an aperiodic oscillatory gliding motility behaviour in Myxococcus xanthus using confocal interference reflection microscopy

2019 ◽  
Author(s):  
Liam M. Rooney ◽  
Lisa S. Kölln ◽  
Ross Scrimgeour ◽  
William B. Amos ◽  
Paul A. Hoskisson ◽  
...  
Keyword(s):  
Myxococcus Xanthus ◽  
Three Dimensional ◽  
Basal Membrane ◽  
Gliding Motility ◽  
The Novel ◽  
Force Transmission ◽  
Topological Information ◽  
Type Iv ◽  
Microscopy Techniques

The Delta-proteobacterium, Myxococcus xanthus, has been used as a model for bacterial motility and to provide insights of bacterial swarming behaviours. Fluorescence microscopy techniques have shown that various mechanisms are involved in gliding motility, but these have almost entirely been limited to 2D studies and there is currently no understanding of gliding motility in a 3D context. We present here the first use of confocal interference reflection microscopy (IRM) to study gliding bacteria, and we reveal aperiodic oscillatory behaviour with changes in the position of the basal membrane relative to the coverglass on the order of 90 nm in vitro. Firstly, we use a model plano-convex lens specimen to show how topological information can be obtained from the wavelength-dependent interference pattern in IRM. We then use IRM to observe gliding M. xanthus and show that cells undergo previously unobserved changes in their height as they glide. We compare the wild-type with mutants of reduced motility, which also exhibit the same changes in adhesion profile during gliding. We find that the general gliding behaviour is independent of the proton motive force-generating complex, AglRQS, and suggest that the novel behaviour we present here may be a result of recoil and force transmission along the length of the cell body following firing of the Type IV pili.

scholarly journals Study on Flexural Bearing Capacity Calculation Method of Enclosure Pile with Partial Excision in Deep Foundation Pit

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Mingfeng Lei ◽  
Linghui Liu ◽  
Yuexiang Lin ◽  
Jin Li
Keyword(s):  
Flexural Strength ◽  
Bearing Capacity ◽  
Calculation Method ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Theoretical Derivation ◽  
Deep Foundation Pit ◽  
Practical Engineering ◽  
Capacity Calculation ◽  
Partial Excision

During deep foundation pit construction, the structural clearance intrusion, which is caused by the complex formation conditions and the inefficient drilling equipment, is usually detected due to the vertical deviation of piles. To meet construction requirements, pile parts intruding into the structural clearance are supposed to be excised. However, the sectional flexural strength of the pile is bound to decrease with partial excision, which would reduce the bearing capacity of the enclosing structure during construction. In this paper, a theoretical derivation of the normal sectional flexural strength of the partially excised circular pile is proposed. The derivation adopts the assumption of the plane section and steel ring equivalence and can be solved by the bisection method. Furthermore, the calculation method is applied to the pile evaluation of a practical engineering; also, the method is verified by the numerical method. The application results show that the excision of rebar and pile’s sectional area will cause a rapid linear decline in the sectional flexural strength. After excising 18 cm radial thickness of the circular pile (ϕ800 mm) and 6 longitudinal rebars, the sectional flexural strength of the pile decreases to 58% from the origin, which cannot meet the support requirement. The analysis indicates that pile reinforcements must be carried out to maintain the construction safety.

Design of a Novel Air Bearing Workbench for Rotary Ultrasonic Drilling of Advanced Ceramics

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Liping Liu ◽  
Bin Lin ◽  
Fengzhou Fang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Bearing Capacity ◽  
Cutting Force ◽  
Air Bearing ◽  
The Novel ◽  
Advanced Ceramics ◽  
Air Damping ◽  
Ultrasonic Drilling ◽  
Rotary Ultrasonic Drilling

A novel air bearing workbench used in rotary ultrasonic drilling of advanced ceramics was designed to constantly and sensitively control the cutting force. Compared with traditional feed systems, the novel air bearing workbench features an aerostatic guide and a pneumatic actuator, so that it only overcomes the air damping when the cutting force is balanced. Thus, it can sensitively and constantly control the cutting force for rotary ultrasonic drilling of advanced ceramics. The aerostatic guide, which determines the eccentric bearing capacity and stiffness of the workbench, is the most important part. The forces applied on the aerostatic guide faces were analyzed to calculate the bearing capacity and stiffness of the workbench using varying gas film thicknesses with finite element method (FEM). Based on the result of the analysis, the best gas film thickness of the aerostatic guide was designed to be 30 μm. The real eccentric bearing capacity and stiffness of the workbench were measured. The error between experimental results and the FEM results was within 12%.

scholarly journals Estimating the Uplift Bearing Capacity of Belled Piers Adjacent to Sloping Ground by Numerical Modeling Based on Field Tests

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yangchun Han ◽  
Jiulong Cheng ◽  
Weifeng Zheng ◽  
Shijun Ding
Keyword(s):  
Numerical Modeling ◽  
Bearing Capacity ◽  
Attenuation Coefficient ◽  
Slope Angle ◽  
Field Tests ◽  
Embedment Depth ◽  
Sloping Ground ◽  
Foundation Model ◽  
The Difference ◽  
The Impact

In order to evaluate the uplift bearing capacity of belled piers beside slopes, a series of numerical simulations are carried out based on field tests data. First, a number of uplift loading tests of full-scale belled piers are carried out on the project site of transmission line in Anhui Province, China. Second, a slope-foundation model for numerical modeling is proposed and calibrated based on field tests data. The behavior of belled piers adjacent to slopes subject to uplift load is studied by numerical modeling. The impact of three parameters, including distance (a) from the belled pier to the crest of the slope, slope angle (β), and embedment depth (h) of the belled pier, has been investigated on the uplift capacity of the belled pier. Based on the simulation results, an attenuation coefficient (ω) is put forward for evaluating the reduction of uplift bearing capacity of the belled pier. The results show that the coefficient ω is negatively correlated with distance a and depth h, and the influence of distance a is greater than that of depth h according to the results of variance analysis, but the difference is not significant by F test. Moreover, the empirical equation between attenuation coefficient ω and three key factors a, β, and h had been presented by a series of fitting.

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