scholarly journals Model Test of Jacked Pile Penetration Process Considering Influence of Pile Diameter

2021 ◽  
Vol 9 ◽  
Author(s):  
Yonghong Wang ◽  
Songkui Sang ◽  
Xueying Liu ◽  
Yongfeng Huang ◽  
Mingyi Zhang ◽  
...  
Keyword(s):  
Penetration Depth ◽  
Axial Force ◽  
Driving Mechanism ◽  
Force Transmission ◽  
Foundation Soil ◽  
Pile Diameter ◽  
Pile Penetration ◽  
Side Resistance ◽  
Different Diameters ◽  
Test Pile

In order to investigate the influence of different diameters on pile end resistance, pile side resistance, pile axial force and pile force transmission law of jacked pile penetration, two pairs of embedded sensitized microfiber grating sensors were installed by slotting the pile body. The pile-jacking process of static-pressing viscous foundation soil with different diameters of closed-tube model piles was successfully monitored. The test results show that the pile pressure, pile end resistance and pile side resistance of the two test piles increase linearly with the increase of pile depth. When the pile jacks, the final pressure of the test pile TP1 is higher than that of the test pile. TP2 is 31% higher, pile end resistance is 18% higher, and total side resistance is 57% higher. The results show that increasing the pile diameter can significantly increase the pile side resistance; under different penetration depths, the pile side resistance is from top to end. Continuously exerted, the axial force of the pile body decreases with the depth of the pile and the slope of the distribution curve of the axial forcegradually decreases. At the maximum penetration depth, the axial force of the pile TP1 is 18% larger than that of the test pile TP2; As the depth increases, the unit side resistance at the same penetration depth gradually decreases, that is, the side resistance has a “degradation effect”; at the end of the pile jacking, the percentage of the pile end resistance to the pile force exceeds 50%, that is, the pile end resistance bears most of the load. This research can be used as a reference for the study of pile driving mechanism in clayey and layered clayey soils.

A Modular Mechanism for Downhole Weight-on-Bit and Torque Reaction in Small Diameter Boreholes

2021 ◽  
pp. 1-15
Author(s):  
Anirban Mazumdar ◽  
Stephen Buerger ◽  
Adam Foris ◽  
Jiann-cherng Su
Keyword(s):  
Axial Force ◽  
Small Diameter ◽  
Field Testing ◽  
Drill String ◽  
Force Transmission ◽  
Drilling Performance ◽  
Weight On Bit ◽  
In Series ◽  
Mechanical Devices ◽  
Scalable Design

Abstract Drilling systems that use downhole rotation must react torque either through the drill-string or near the motor to achieve effective drilling performance. Problems with drill-string loading such as buckling, friction, and twist become more severe as hole diameter decreases. Therefore, for small holes, reacting torque downhole without interfering with the application of weight-on-bit, is preferred. In this paper we present a novel mechanism that enables effective and controllable downhole weight on bit transmission and torque reaction. This scalable design achieves its unique performance through four key features: 1) mechanical advantage based on geometry, 2) direction dependent behavior using rolling and sliding contact, 3) modular scalability by combining modules in series, and 4) torque reaction and weight on bit that are proportional to applied axial force. As a result, simple mechanical devices can be used to react large torques while allowing controlled force to be transmitted to the drill bit. We outline our design, provide theoretical predictions of performance, and validate the results using full-scale testing. The experimental results include laboratory studies as well as limited field testing using a percussive hammer. These results demonstrate effective torque reaction, axial force transmission, favorable scaling with multiple modules, and predictable performance that is proportional to applied force.

scholarly journals Study on the horizontal bearing characteristics of pile foundation in coral sand

2021 ◽  
Author(s):  
Chunyan Wang ◽  
Hanlong Liu ◽  
Xuanming Ding ◽  
Chenglong Wang ◽  
Qiang Ou
Keyword(s):  
Lateral Displacement ◽  
Experimental Studies ◽  
Deformation Characteristic ◽  
Bending Moment ◽  
Silica Sand ◽  
Pile Head ◽  
Pile Diameter ◽  
Coral Sand ◽  
Horizontal Pressure ◽  
Different Diameters

This paper presents the horizontal bearing characteristics of piles in coral sand and silica sand from comparative experimental studies. A total of 6 model piles with different diameters are tested. The horizontal bearing capacity, deformation characteristic, bending moment, p-y curve, the change in soil horizontal pressure, as well as the particle breakage behaviour of coral sand are investigated. The results show that, in coral sand foundation, the horizontal bearing capacities of piles and the increments of soil horizontal pressures are obviously greater than those in silica sand. Accordingly, the lateral displacement, the rotation of pile head, the bending moment and the corresponding distribution depth in coral sand are significantly smaller than that in silica sand. The p-y curves indicate that the horizontal stiffness of coral sand is greater than that of silica sand. Remarkably, the breakage behaviour of coral sand is mainly distributed in the range of 10 times pile diameter depth and 5 times pile diameter width on the side where the sand is squeezed by pile. Furthermore, in coral sand, the influence of pile size is more pronounced, the squeezing force generated by pile spread farther and its influence range is larger compared to those in silica sand.

scholarly journals Determination of mechanical properties of soil under laboratory conditions

2014 ◽  
Vol 60 (Special Issue) ◽  
pp. S66-S69 ◽  
Author(s):  
V. Malý ◽  
M. Kučera
Keyword(s):  
Mechanical Properties ◽  
Penetration Depth ◽  
Measuring Device ◽  
Laboratory Conditions ◽  
Measuring Network ◽  
Set Up ◽  
Different Diameters ◽  
Different Levels ◽  
Properties Of Soil

This paper presents the mechanical properties of soil. In order to determine the properties of soil under laboratory conditions, a special measuring device was constructed, viz. a bevameter. Two types of soil with different levels of moisture were examined and their mechanical properties were determined. Measurements were taken of non-compressed soil. A measuring network was set up, consisting of measuring and recording devices. In the course of measuring, the force and penetration depth of the pressing plate were recorded simultaneously. Three different diameters of pressing plate were used, namely 38, 50 and 70 mm. The pressure on the contact area was calculated after completion of the measurements, and the relationships between pressure and penetration depth were presented graphically.

scholarly journals An Optimal Design of Driving Mechanism in a 1 Degree of Freedom (d.o.f.) Anthropomorphic Finger

2005 ◽  
Vol 2 (2) ◽  
pp. 103-110 ◽  
Author(s):  
M. Ceccarelli ◽  
N. E. N. Rodríguez ◽  
G. Carbone ◽  
C. Lopez-Cajùn
Keyword(s):  
Optimization Problem ◽  
Evaluation Criteria ◽  
Design Procedure ◽  
Degree Of Freedom ◽  
Driving Mechanism ◽  
Multi Objective Optimization ◽  
Force Transmission ◽  
Driving Mechanisms ◽  
Finger Motion ◽  
Actuation Systems

Mechanisms can be used in finger design to obtain suitable actuation systems and to give stiff robust behavior in grasping tasks. The design of driving mechanisms for fingers has been attached at LARM in Cassino with the aim to obtain one degree of freedom actuation for an anthropomorphic finger. The dimensional design of a finger-driving mechanism has been formulated as a multi-objective optimization problem by using evaluation criteria for fundamental characteristics regarding with finger motion, grasping equilibrium and force transmission. The feasibility of the herein proposed optimum design procedure for a finger-driving mechanism has been tested by numerical examples that have been also used to enhance a prototype previously built at LARM in Cassino.

Experimental Studies on Loads Acting on Two Piles of Side-by-Side Arrangements in the Uniform Flow

2012 ◽  
Vol 226-228 ◽  
pp. 1785-1788
Author(s):  
Zhao Qing Zhu ◽  
Guo Liang Dai
Keyword(s):  
Drag Coefficient ◽  
Flow Velocity ◽  
Experimental Studies ◽  
Reynolds Numbers ◽  
Uniform Flow ◽  
Drag Forces ◽  
Pile Diameter ◽  
Two Component ◽  
Balance Analysis ◽  
Different Diameters

Indoor model experiments were made to study drag loads on two piles of side-by-side arrangements in the uniform flow. Take three different velocities of the flow, three different diameters of piles and five different distances of two piles in the experiments to get the variations of loads. Drag forces were measured by a two-component balance. Analysis on experiment results shows that drag forces increase with the increase of the pile diameter, the increase of the flow velocity and the decrease of the distance of two piles. The drag coefficient CDunder different Reynolds numbers shows the same change law. The drag coefficient CDdecreases with the increase of the distance of two piles and has good coherence to the ratio of the distance of two piles to the pile diameter.

scholarly journals Laboratory Test of the Soil Compaction

2015 ◽  
Vol 63 (1) ◽  
pp. 77-85
Author(s):  
Vlastimil Malý ◽  
František Tóth ◽  
Jan Mareček ◽  
Eva Krčálová
Keyword(s):  
Mechanical Properties ◽  
Penetration Depth ◽  
Soil Compaction ◽  
Measuring Device ◽  
Special Measuring ◽  
Measuring Network ◽  
Set Up ◽  
Different Diameters ◽  
Different Levels ◽  
Properties Of Soil

This paper presents the mechanical properties of soil. In order to determine the properties of soil under laboratory conditions, we made use of a special measuring device, viz. a bevameter. Two types of soil with different levels of moisture were examined and their mechanical properties determined. Measurements were taken of non pressed and compressed soil. A measuring network was set up, consisting of measuring and recording devices. In the course of measuring, the force and penetration depth of the pressing plate were recorded simultaneously. Four different diameters of pressing plate were used, resp. 25, 38, 50 and 70 mm. The pressure on the contact area was calculated after completion of the measurements, and the relationships between pressure and penetration depth were presented graphically.

Experimental Study on the Mechanics of a Coiled Tubing Working Within a Marine Riser Under the Affection of Marine Loads

2019 ◽  
Author(s):  
Yingchun Chen ◽  
Chang Wang ◽  
Xinhua Wang ◽  
Wenming Wang ◽  
Wenda Wang
Keyword(s):  
Axial Force ◽  
Oil And Gas ◽  
Excitation Frequency ◽  
Experimental System ◽  
Transfer Efficiency ◽  
Force Transmission ◽  
Marine Riser ◽  
External Excitation ◽  
Pipe System ◽  
Coiled Tubing

Abstract Due to its unique advantages, coiled tubing is now widely used in marine oil and gas exploitation operations, while the mechanical behavior of coiled tubing working within a marine riser affected by marine loads is still unknown. By building an indoor simulation experimental system, the mechanics of this pipe-in-pipe system was studied, and the effect of the lateral excitation on the axial force transmission of inner pipe was clarified. It was found that, when the external excitation frequency was within the first natural frequency range of the outer pipe, the external excitation would increase the axial load transfer efficiency of the inner pipe, and the axial force transfer efficiency of the inner tube would reach the maximum when the resonance of out pipe occurred. The results can be helpful on the understanding of mechanics of a coiled tubing working within a marine riser.

scholarly journals Computerized method for estimation of ultimate load of piles

2018 ◽  
Vol 230 ◽  
pp. 02002
Author(s):  
Basheer Younis ◽  
Khudhair Thamer ◽  
Firas Kazimahomedov
Keyword(s):  
Present Method ◽  
Ultimate Load ◽  
Degree Polynomial ◽  
Maximum Settlement ◽  
Pile Test ◽  
Pile Diameter ◽  
Polynomial Fit ◽  
Pile Settlement ◽  
The Mean ◽  
Test Pile

A new method was established to estimate the ultimate load, which is utilized in the assessment of pile test. In the present study twenty five reports of failure test piles (28.5 x 28.5 cm in dimensions, 12 m in depth and the working load was 40 ton) of Um-Alqura Mosque project were studied in according to their loading and settlement. The (mean ± SD) of the pile settlement for each load of all piles studied were determined, and the results obtained were utilized to generate the equation that correlates between the load and settlement using (4th degree polynomial fit graph). The equation obtained was applied to estimate the ultimate load for the maximum settlement (10% of the pile diameter). The estimated ultimate load (130 ton) in the present study was compared with the ultimate load (132 ton), which was determined previously using (Fellenius and Decourt presentation, 2001). The deviation between the ultimate load of the previous and the present method was (1.5%), but the present method depends on two working load, so it saves time and efforts and suitable to implement in the assessment of the test pile.

Axial force transmission in flexible bowtie dielectric elastomer actuators

2022 ◽  
Vol 120 (1) ◽  
pp. 012903
Author(s):  
Gih-Keong Lau ◽  
Fa-Yi Chen ◽  
Zhe-Xian Ren
Keyword(s):  
Axial Force ◽  
Dielectric Elastomer ◽  
Force Transmission ◽  
Dielectric Elastomer Actuators

Burr-Free Microblanking Using Piezoelectric Actuator

2004 ◽  
Vol 126 (4) ◽  
pp. 653-658 ◽  
Author(s):  
Isamu Aoki ◽  
Masahiro Sasada
Keyword(s):  
Penetration Depth ◽  
Piezoelectric Actuator ◽  
Copper Foil ◽  
Design Method ◽  
Driving Mechanism ◽  
Drive Mechanism ◽  
Depth Use

Burr-free blanking requirements are strong; however, the thinner the product, the more difficult the burr-free blanking will be, due mainly to the control of the punch penetration depth. In this study, the principle of accompanying burr-free blanking problems, and the driving mechanism of methods for realizing burr-free blanking of foil were realized. The conditions for realizing successful burr-free blanking are the clearance of step 1 and punch penetration depth. Use of the piezoelectric actuator element and the design method for this was proposed as the punch drive mechanism. Good results were obtained by using this press machine for burr-free blanking of 50 μm copper foil.

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