Field Testing of Axial Performance of Large-Diameter Helical Piles at Two Soil Sites

2018 ◽  
Vol 144 (3) ◽  
pp. 06017021 ◽  
Author(s):  
Weidong Li ◽  
D. J. Y. Zhang ◽  
D. C. Sego ◽  
Lijun Deng
Keyword(s):  
Large Diameter ◽  
Field Testing ◽  
Helical Piles

scholarly journals A Preliminary Study on the Design Method for Large-Diameter Deep-Hole Presplit Blasting and Its Vibration-Isolation Effect

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Shuangshuang Xiao ◽  
Hongsheng Wang ◽  
Guowei Dong
Keyword(s):  
Vibration Isolation ◽  
Design Method ◽  
Blast Hole ◽  
Large Diameter ◽  
Field Testing ◽  
Open Pit ◽  
Vibration Velocity ◽  
Deep Hole ◽  
Charge Mass ◽  
Presplit Blasting

Presplit blasting can reduce vibration and back impact induced by cast blasting, thus resulting in a smooth bench slope. To design reasonable presplit blasting parameters, this research investigated the formation of presplit faces based on the explosion mechanics and revealed the cracking mechanism of presplit blasting. According to the stress distribution in the vicinity of the blast holes under the action of explosive stress waves and blasting gas, we deduced theoretical formulae for parameters including charge mass in blast holes, hole spacing, and distance from presplit blast holes to cushion holes. On this basis, a method was proposed for the design of large-diameter deep-hole presplit blasting. Field testing was conducted by setting different spacing for presplit blast holes, to monitor the blasting-induced vibration. The results showed that appropriate hole spacing can reduce the particle vibration velocity and the attenuation index of blasting-induced vibration changed slightly while the attenuation coefficient decreased significantly; the formed presplit faces were smooth and had a high half-cast factor. Finally, the reasonable hole spacing for presplit blasting, distance from presplit blast hole to the cushion hole, and the charge mass in blast holes in the Heidaigou open-pit coal mine were determined, respectively.

Testing Study on Bearing Behavior of Belled Large-Diameter PHC Pipe Pile by NAKS (Nakabori Kakutei System) Construction Method

2013 ◽  
Vol 353-356 ◽  
pp. 533-539 ◽  
Author(s):  
Wen Xu ◽  
Yu Bin Hou
Keyword(s):  
Bearing Capacity ◽  
Large Diameter ◽  
Field Testing ◽  
Construction Method ◽  
Load Test ◽  
Test Field ◽  
Static Load Test ◽  
Pipe Pile ◽  
Bored Pile ◽  
Bearing Behavior

Through field static load test and pile shaft axial force test, field testing study is conducted on bearing behavior of NAKS-construction-method belled large-diameter PHC pipe pile; besides, the test result is compared with that of hammering-method PHC pipe pile and bored pile with same pile length and diameter under the same site condition. The result shows that the ultimate bearing capacity of NAKS-construction-method belled large-diameter PHC pipe pile is slightly inferior to hammering-method PHC pipe pile but obviously superior to that of bored pile. Compared with traditional hammering-method pipe pile, the pile side resistance of NAKS-construction-method belled pipe pile is smaller; however, the higher toe resistance will give better play to bearing capacity of bearing stratum of pile toe; moreover, it is found that under the action of ultimate load and failure load, the maximum settlement and final settlement of NAKS-construction-method belled pipe pile tip are obviously lower than that of other test piles, which is conductive to lessening foundation settlement of upper structure.

scholarly journals Large-diameter helical pile capacity – torque correlations

2017 ◽  
Vol 54 (7) ◽  
pp. 968-986 ◽  
Author(s):  
Jared Harnish ◽  
M. Hesham El Naggar
Keyword(s):  
Large Diameter ◽  
Failure Criteria ◽  
Load Test ◽  
Ultimate Capacity ◽  
Pile Capacity ◽  
Shearing Resistance ◽  
Helical Piles ◽  
Torque Capacity ◽  
Load Tests ◽  
Pile Load Tests

Large-diameter helical piles are utilized increasingly to support heavy structures. Both the magnitude of the required installation torque and the pile capacity can be directly attributed to the soil shearing resistance developed over the embedded area of the pile including the shaft and helical plates. Hence, the pile capacity can be correlated to installation torque. Such correlations are widely used in the helical pile industry as a means for quality control and quality assurance. In the current study, a total of 10 test piles were installed while monitoring the installation torque continuously with depth. The recorded installation torque profiles were demonstrated to be accurate and repeatable. Field pile load tests were conducted and their results were analyzed to determine the interpreted ultimate capacity of the test piles. The results demonstrate that the ultimate capacity of large-diameter helical piles can be interpreted from pile load test data employing the failure criteria proposed by Elkasabgy and El Naggar in 2015 and Fuller and Hoy in 1970. The measured installation torque and corresponding ultimate capacity values were employed to define torque–capacity correlation (Kt) based on embedded pile area. It was demonstrated that the proposed Kt is suitable for large-diameter helical piles.

Special Issue on Advanced Maintenance Robots

1995 ◽  
Vol 7 (5) ◽  
pp. 353-353
Author(s):  
Hidemi Hosokai ◽  
Keyword(s):  
Force Control ◽  
Large Diameter ◽  
Cooling Water ◽  
Field Testing ◽  
Special Issue ◽  
Inspection Robot ◽  
High Rise ◽  
Fire Extinguishing ◽  
Human Operators ◽  
Adverse Environments

At present, inspection and maintenance operations on various types of pipelines, structures, and others are carried out manually by human operators. Such operations are often performed, in general, under adverse environments such as high places and narrow areas. In addition, fire fighters in blazing high-rise buildings may be subjected to dangers involving high places and fires. Moreover, the robotization of grinding work in factories, for example, require a large number of empirical technologies. In order to mechanize tasks under such adverse environments and under special working conditions, research has been conducted, including studies of mobile mechanisms on inner walls and outer walls of piping, on wall surfaces of structures, etc. or studies of force control methods. Under these circumstances, this issue will be specialized in technical progress of various types of maintenance robots. First, a navigation system of a wind quantity inspection robot using a fuzzy neural network will be discussed by Messrs. Fukuda and Abe. Next, a report will be given by Messrs. Ishikawa and Shiire on the mechanism and functions of a pile recovery robot for large-diameter pipes, with a view to carrying out cleaning work inside cooling water pipes of electric power generation plants, as well as on its field testing. Furthermore, Messrs. Kawaguchi and Yoshida will be asked to report on the mechanism of an inspection robot for use on the inner surfaces of gas piping buried in the ground. In addition, a discussion will be carried out by Messrs. Naruse and Takada on the mechanism and fire extinguishing capability of a hybrid robot system for use in combatting fires in high-rise buildings. Moreover, Messrs. Ozaki and Jinno will be discussing the mechanism and force control system of a grinding robot. In addition, a discussion will be carried out by Messrs. Hosokai and Hara regarding the motion function of a piping inspection robot having a lazy tong mechanism and also regarding its piping test results. Finally, Messrs. Amano and Kakikura will be called upon to give a discussion concerning a robot for carrying out exfoliation of finishing materials on the outer walls of structures and its exfoliation. In closing, it is hoped that this special issue will be of some help in the future when such maintenance robots are developed.

A new modified approach to evaluating the installation power of large-diameter helical piles in sand validated by centrifuge and field data

2021 ◽  
Vol 114 ◽  
pp. 102756
Author(s):  
Kang Shao ◽  
Qian Su ◽  
Kaiwen Liu ◽  
Guoxia Shao ◽  
Zhibin Zhong ◽  
...  
Keyword(s):  
Field Data ◽  
Large Diameter ◽  
Helical Piles

Laboratory and Field Testing of Large-Diameter Plastic Pipe

1997 ◽  
Vol 1594 (1) ◽  
pp. 208-216 ◽  
Author(s):  
P. R. Fleming ◽  
E. Faragher ◽  
C. D. F. Rogers
Keyword(s):  
Laboratory Test ◽  
Design Method ◽  
Large Diameter ◽  
Field Testing ◽  
Theoretical Method ◽  
Test Methods ◽  
Soil System ◽  
The United Kingdom ◽  
Plastic Pipe ◽  
Laboratory Test Results

Flexible plastic pipe is increasingly being used in the United Kingdom for drainage and ducting (conduit) purposes. This increase in use is leading to the introduction of larger-diameter pipes. The U.K. Department of Transport (DoT) uses a recently developed, theoretical method to specify installation conditions in place of traditional techniques (e.g., Spangler’s Iowa method). The DoT design method is outlined. The extensive program of laboratory and field testing carried out at Lough-borough University to determine the performance of plastic pipes under a range of loading conditions that may be expected in practice is then described. Laboratory test results compared well with the results obtained in the field once the different boundary conditions were accounted for, thereby validating the laboratory test methods by suggesting how allowance for field conditions can be made. Some reference is made to the shapes of deformation (determined from circumferential strain data) and the effect of installation conditions upon them. Pipe deformations were found to be well within acceptable, conservative limits under all load regimens, and near equilibrium of the pipe-soil system was established relatively quickly following application of a static or a dynamic load sequence to it.

Development of a digital SEM

1991 ◽  
Vol 49 ◽  
pp. 358-359
Author(s):  
A. Yamada ◽  
A. Shibano ◽  
K. Harasawa ◽  
T. Kobayashi ◽  
H. Fukuda ◽  
...  
Keyword(s):  
Large Diameter ◽  
Objective Lens ◽  
Large Specimen ◽  
Backscattered Electrons ◽  
Digital Scanning ◽  
Junction Type ◽  
High Resolution Images ◽  
Working Distance ◽  
Type Detector ◽  
Short Working

A newly developed digital scanning electron microscope, the JSM-6300, has the following features: Equipped with a narrower conical objective lens (OL), it allows high resolution images to be obtained easily at a short working distance (WD) and a large specimen tilt angle. In addition, it is provided with automatic functions and digital image processing functions for ease of operation.Conical C-F lens: The newly developed conical C-F objective lens, having low aberration characteristics over a wide WD range, allows a large-diameter (3-inch) specimen to be tilted up to 60° at short WD, and provides images with low magnifications starting at 10*. On the bottom of the lens, a p n junction type detector is provided to detect backscattered electrons (BE) from the specimen. As the narrower conical 0L increases the secondary electron (SE) detector's field intensity on the specimen surface, high SE image quality is obtained.

Field testing the AMIT Job Performance Aid: Methods, results, and implications for the Air Force maintenance community

2007 ◽  
Author(s):  
David E. Kancler ◽  
Christopher C. Curtis ◽  
Darryl S. Stimson ◽  
Johnnie Jernigan
Keyword(s):  
Job Performance ◽  
Air Force ◽  
Field Testing ◽  
Force Maintenance
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