scholarly journals Potential and prospects of photocatalytic disinfection: using sustainable solarenergy- driven photocatalysts

2021 ◽  
Vol 28 (4) ◽  
pp. 165-175
Author(s):  
Juhua He ◽  
Kenny W K Hui ◽  
Irene M C Lo
Keyword(s):  
Hong Kong ◽  
Measurement System ◽  
Measurement Accuracy ◽  
Large Diameter ◽  
Housing Projects ◽  
Bored Pile ◽  
Accuracy And Precision ◽  
Bored Piles ◽  
Pile Type ◽  
Sonic Logging

A new measurement system called Crosshole Sonic Logging Tomography (CSLT) provides information on the size, shape, and orientation of defects in a bored pile. The CSLT measurement system has not (yet) been accredited in Hong Kong for foundation testing. Bored piles in Hong Kong are generally wide and deep. Existing measurement accuracy studies do not consider this large type of bored piles. The objective of this research is to quantify the measurement accuracy and precision of the CSLT method for large diameter bored piles (the most common pile type for public housing projects in Hong Kong). A test pile was constructed with known defects and perform experiments with a CSLT measurement system to quantify its accuracy and precision. CSLT is found to be accurate in detecting shape, size, and location of large defects but small defects close to the tube are difficult to detect. Generally speaking, CSLT has satisfactory accuracy and precision for practical use. The use of CSLT can be considered as a feasible method in defect diagnosis of bore piles in Hong Kong.

scholarly journals Accuracy and precision of the CSLT measurement system: An experiment to defect diagnoses in bored piles

2021 ◽  
Vol 28 (4) ◽  
pp. 176-185
Author(s):  
Zezhong Wang ◽  
Eric Tak Cho Ho ◽  
Inez Maria Zwetsloot
Keyword(s):  
Hong Kong ◽  
Measurement System ◽  
Measurement Accuracy ◽  
Large Diameter ◽  
Housing Projects ◽  
Bored Pile ◽  
Accuracy And Precision ◽  
Bored Piles ◽  
Pile Type ◽  
Sonic Logging

A new measurement system called Crosshole Sonic Logging Tomography (CSLT) provides information on the size, shape, and orientation of defects in a bored pile. The CSLT measurement system has not (yet) been accredited in Hong Kong for foundation testing. Bored piles in Hong Kong are generally wide and deep. Existing measurement accuracy studies do not consider this large type of bored piles. The objective of this research is to quantify the measurement accuracy and precision of the CSLT method for large diameter bored piles (the most common pile type for public housing projects in Hong Kong). A test pile was constructed with known defects and perform experiments with a CSLT measurement system to quantify its accuracy and precision. CSLT is found to be accurate in detecting shape, size, and location of large defects but small defects close to the tube are difficult to detect. Generally speaking, CSLT has satisfactory accuracy and precision for practical use. The use of CSLT can be considered as a feasible method in defect diagnosis of bore piles in Hong Kong.

scholarly journals Influence of a permanent liner on the skin friction of large-diameter bored piles in Hong Kong granitic saprolites

2003 ◽  
Vol 40 (4) ◽  
pp. 793-805 ◽  
Author(s):  
S -C.R Lo ◽  
K S Li
Keyword(s):  
Numerical Simulation ◽  
Hong Kong ◽  
Skin Friction ◽  
Large Diameter ◽  
Full Length ◽  
Load Test ◽  
Test Results ◽  
Local Method ◽  
Bored Pile ◽  
Bored Piles

The skin friction of large-diameter bored piles in Hong Kong granitic saprolite manifested high variability. The influence of one construction detail, a full-length permanent liner, is studied by examining full-scale load test results and by numerical simulation of this construction detail. It is concluded that the use of a full-length liner will give very low skin friction because the local method of constructing a large-diameter bored pile with a full-length permanent liner leads to a significant reduction in radial stress acting on the pile–soil interface.Key words: construction, pile, stress, skin friction, numerical simulation.

scholarly journals Determining the quantity of access tubes for quality control of bored pile concrete based on probability approach

2020 ◽  
Vol 14 (2) ◽  
pp. 76-86
Author(s):  
Bach Duong
Keyword(s):  
Quality Control ◽  
National Standard ◽  
Construction Process ◽  
Construction Stage ◽  
Probability Approach ◽  
Bored Pile ◽  
Defects Inspection ◽  
Concrete Quality ◽  
Bored Piles ◽  
Sonic Logging

Unexpected defects of concrete in a completed bored pile can arise during the construction stage. Therefore, post-construction testing of bored pile concrete is an important part of the design and construction process. The Cross-hole Sonic Logging (CSL) method has been the most widely used to examine the concrete quality. This method requires some access tubes pre-installed inside bored piles prior to concreting; the required quantity of access tubes has been pointed out in few literatures and also ruled in the national standard of Vietnam (TCVN 9395:2012). However, theoretical bases aiming to decide the required quantity of access tubes have not been given yet. A probability approach is proposed in this paper aiming to determine the essential quantity of access tubes, which depend not only on pile diameters, magnitude of defects, but also on the technical characteristics of CSL equipment. Keywords: access tubes; bored piles; CSL method; defects; inspection probability.

scholarly journals Acoustic measurements of bored pile length using two channels

2020 ◽  
Vol 22 (4) ◽  
pp. 180-191 ◽  
Author(s):  
D. G. Samarin ◽  
V. L. Ustyuzhanin ◽  
A. A. Lobanov
Keyword(s):  
Elastic Waves ◽  
Measurement Accuracy ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Bored Pile ◽  
Acoustic Methods ◽  
Advance Research ◽  
Bored Piles ◽  
Non Destructive ◽  
Pile Length

Non-destructive testing of structures is an effective way to determine their required parameters. One of the promising directions is the acoustic measurement of the pile length using two channels. This method is based on the excitation and registration of elastic waves on the pile surface. A limitation of acoustic methods is that the speed of the elastic waves in the pile is assumed to be known in advance. Research results show that the practical application of this condition can lead to a significant error. This is especially true for bored piles, where the speed of the elastic wave propagation is determined by many different factors. This paper proposes to increase the measurement accuracy of the acoustic wave speed in the bored pile. The use of two measurement channels, which implies the introduction of the specified distance between the receiving devices, made it possible to increase the measurement accuracy up to 5 %.

scholarly journals STUDY OF THE INFLUENCE OF A BORED PILE DIAMETER ON CHANGE OF COEFFICIENT OF SUBGRADE REACTION AT CALCULATION FOR HORIZONTAL LOADS

2019 ◽  
Vol 9 (4) ◽  
pp. 11-15
Author(s):  
Airat Z. GAISIN ◽  
Sergey A. KRUTYAEV ◽  
Anton O. GLAZACHEV
Keyword(s):  
Large Diameter ◽  
Three Dimensional ◽  
Bending Moment ◽  
Soil Conditions ◽  
Subgrade Reaction ◽  
Pile Head ◽  
Bored Pile ◽  
Pile Diameter ◽  
Numerical Studies ◽  
Bored Piles

The problem of designing foundations using long bored piles of large diameter is shown. Such piles are most often used in the construction of buildings and structures, on the foundations of which large loads are transferred, and such buildings are often built on sites with difficult soil conditions. When designing foundations using such piles, it becomes necessary to calculate them for horizontal load and bending moment. The article is devoted to studies of the dependence of the coefficient of subgrade reaction on the diameter of piles when calculating long bored piles of large diameter in clay soils. To determine the patt erns of changes in the coefficient of subgrade reaction from the diameter of the piles, numerical studies in a three-dimensional setting were performed. Based on the results obtained, the graphs «load - displacement» are constructed. The method of calculating the coefficient of subgrade reaction with known movements of the pile head and the applied load is shown. The regularities of changes in the deformability of the soil base with an increase in the diameter of the pile are revealed and a coefficient taking into account this dependence is proposed.

Response of Laterally Loaded Large-Diameter Bored Pile Groups

2001 ◽  
Vol 127 (8) ◽  
pp. 658-669 ◽  
Author(s):  
Charles W. W. Ng ◽  
Limin Zhang ◽  
Dora C. N. Nip
Keyword(s):  
Large Diameter ◽  
Pile Groups ◽  
Bored Pile ◽  
Laterally Loaded

Multifrequency full-waveform sonic logging in the screened interval of a large-diameter production well

Geophysics ◽  
2013 ◽  
Vol 78 (5) ◽  
pp. B243-B257 ◽  
Author(s):  
Majed Almalki ◽  
Brett Harris ◽  
J. Christian Dupuis
Keyword(s):  
Phase Velocity ◽  
Velocity Dispersion ◽  
Large Diameter ◽  
Low Frequency ◽  
Production Well ◽  
Frequency Wave ◽  
Full Waveform ◽  
Phase Velocity Dispersion ◽  
Production Wells ◽  
Sonic Logging

A set of field experiments using multiple transmitter center frequencies was completed to test the application potential of low-frequency full-waveform sonic logging in large-diameter production wells. Wireline logs were acquired in a simple open drillhole and a high-yield large diameter production well completed with wire-wound sand screens at an aquifer storage and recovery site in Perth, Western Australia. Phase-shift transform methods were applied to obtain phase-velocity dispersion images for frequencies of up to 4 kHz. A 3D representation of phase-velocity dispersion was developed to assist in the analysis of possible connections between low-frequency wave propagation modes and the distribution of hydraulic properties. For sandstone intervals in the test well, the highest hydraulic conductivity intervals were typically correlated with the lowest phase velocities. The main characteristics of dispersion images obtained from the sand-screened well were highly comparable with those obtained at the same depth level in a nearby simple drillhole open to the formation. The sand-screened well and the open-hole displayed an expected and substantial difference between dispersion in sand- and clay-dominated intervals. It appears that for clay-dominated formations, the rate of change of phase velocity can be associated to clay content. We demonstrated that with appropriate acquisition and processing, multifrequency full-waveform sonic logging applied in existing large-diameter sand-screened wells can produce valuable results. There are few wireline logging technologies that can be applied in this setting. The techniques that we used would be highly suitable for time-lapse applications in high-volume production wells or for reassessing formation properties behind existing historical production wells.

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