The Experts below are selected from a list of 72 Experts worldwide ranked by ideXlab platform
Wei-ming Gong - One of the best experts on this subject based on the ideXlab platform.
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Field study on post-grouting effects of cast-in-place bored Piles in extra-thick fine sand layers
Acta Geotechnica, 2019Co-Authors: Zhi-hui Wan, Guo-liang Dai, Wei-ming GongAbstract:The post-pressure grouting technique has proven to be an effective method to enhance axial resistance. In this paper, field tests were conducted to investigate the performances of large-diameter cast-in-place bored Piles for six combined side-and-tip grouting Piles and two side-grouting Piles in extra-thick fine sand layers. The load–displacement response, shaft resistance, and mobilization of unit base resistance were discussed. The field results indicate that compared with the Piles before post-grouting both the shaft resistance and base resistance for the Piles after post-grouting are significantly improved. The Piles after post-grouting have higher load-bearing capacity. Meanwhile, the load-bearing capacity of combined-grouting Piles is also greater than that of side-grouting Piles. Additionally, the strengthening effect of the surrounding soil improvement due to side grouting on the base resistance can enhance the unit base resistance, and the unit shaft resistance can also be increased by the soil improvement at the Pile tip due to tip grouting. Moreover, the distribution of the injected pressurized grout at the Pile tip and side is detected by an electromagnetic wave computerized tomography (EWCT) technique. The results reveal that EWCT can detect the distribution pattern of the Pile, injected grout and geotechnical interface and evaluate the diffusion range of the grout of the soil at the Pile tip and side, which can be used to assess the grouting effect of Grouted Piles. Finally, an in situ standard penetration test is employed to evaluate the grouting effect of Grouted Pile by variation of the SPT N value before and after post-grouting. The research results have reference value and guiding significance for the design and effect detection of post-grouting Piles.
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Research on the Load Settlement Relationship of Post-Grouted Based on the Load Transfer Function Method on Yueqing Bay Bridge
Bridging the East and West, 2016Co-Authors: Wei-ming Gong, Faheem RizviAbstract:Yueqing Bay Bridge test Pile program is located in Zhejiang Province, China. To improve the bearing capacity and decrease the settlement of the Pile, a Pile is conducted in the filed by the method of tip pressure grouting. The analyzed drilled shaft has a diameter of 2.0 m and a length of 88 m. The post Grouted Pile compared to non-Grouted Pile are believed to be related to the side friction reinforcing effect, which is due to the grout penetration upward along the sides of the Pile. It is also related to an enlarge tip area due to the formation of grout bulb, which pre-compresses the soil under the Pile tip, and results in tip resistance and stiffness improvements of Piles due to tip pressure grouting. This paper investigates the contribution of these factors based on load transfer function method analyses applied to a case history. The bearing capacity of post Grouted Pile is analyzed by single factor, which shows that the single factor is not sufficient to predict the load settlement curve of post Grouted Pile. Considering the combined influence of these three factors, the prediction of the load settlement curve is consistent with the measured curve. The results indicate that the effect factor of post Grouted Pile is improved by these three factors.
Liu Xingwang - One of the best experts on this subject based on the ideXlab platform.
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load settlement relationship prediction for Grouted Pile based on load transfer function method
Journal of the Harbin Institute of Technology, 2012Co-Authors: Liu XingwangAbstract:To obtain a good prediction of the Grouted Pile behavior under vertical loads,an iteration method based on the hyperbolic load transfer function is developed to determine the load settlement relationship of the Grouted Pile in this paper.The calculation procedure for a single Grouted Pile in layered soil is presented.Four improvement factors are introduced to account for the effect of grouting on the side friction and end resistance.The empirical range of the improvement factor is also given based on statistical analysis.Finally,a case history is cited to indicate the validity of the presented method.The results show that the presented method can predict the range of load settlement relationship of the Pile head well.It is suggested that the predicted lower bound can be used for a conservative design.
Faheem Rizvi - One of the best experts on this subject based on the ideXlab platform.
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Research on the Load Settlement Relationship of Post-Grouted Based on the Load Transfer Function Method on Yueqing Bay Bridge
Bridging the East and West, 2016Co-Authors: Wei-ming Gong, Faheem RizviAbstract:Yueqing Bay Bridge test Pile program is located in Zhejiang Province, China. To improve the bearing capacity and decrease the settlement of the Pile, a Pile is conducted in the filed by the method of tip pressure grouting. The analyzed drilled shaft has a diameter of 2.0 m and a length of 88 m. The post Grouted Pile compared to non-Grouted Pile are believed to be related to the side friction reinforcing effect, which is due to the grout penetration upward along the sides of the Pile. It is also related to an enlarge tip area due to the formation of grout bulb, which pre-compresses the soil under the Pile tip, and results in tip resistance and stiffness improvements of Piles due to tip pressure grouting. This paper investigates the contribution of these factors based on load transfer function method analyses applied to a case history. The bearing capacity of post Grouted Pile is analyzed by single factor, which shows that the single factor is not sufficient to predict the load settlement curve of post Grouted Pile. Considering the combined influence of these three factors, the prediction of the load settlement curve is consistent with the measured curve. The results indicate that the effect factor of post Grouted Pile is improved by these three factors.
J A Yura - One of the best experts on this subject based on the ideXlab platform.
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strength and behavior of Grouted Pile to sleeve connections
Journal of Structural Engineering-asce, 1991Co-Authors: W B Lamport, James O Jirsa, J A YuraAbstract:Eighteen Grouted Pile-to-sleeve connections were tested to examine the influence of combined loading, relative shear-key location between Pile and sleeve, Pile-sleeve eccentricity, and grout strength. The results indicated that combined loading had no detrimental effect on ultimate capacity of a Grouted connection. Ultimate capacity was not affected by the position of shear-keys in the Pile relative to those in the sleeve or by thickness variations in the grout annulus. The capacity of connections varied with the square root of the grout strength. Results were compared with recognized empirical formulations. The results indicated that safety factors could be reduced and yet maintain acceptable safety indices. Examination of tested Grouted-connection specimens indicated that the major load-resisting mechanisms are grout compression struts and friction that develops at the grout-steel interface. A simplified analytical model was developed using concrete constitutive relationships, and various geometric and material parameters were investigated. The analytical results indicated that increases in shear-key height or reduction of shear-key spacing may not lead to higher ultimate strength of the connection.
W B Lamport - One of the best experts on this subject based on the ideXlab platform.
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strength and behavior of Grouted Pile to sleeve connections
Journal of Structural Engineering-asce, 1991Co-Authors: W B Lamport, James O Jirsa, J A YuraAbstract:Eighteen Grouted Pile-to-sleeve connections were tested to examine the influence of combined loading, relative shear-key location between Pile and sleeve, Pile-sleeve eccentricity, and grout strength. The results indicated that combined loading had no detrimental effect on ultimate capacity of a Grouted connection. Ultimate capacity was not affected by the position of shear-keys in the Pile relative to those in the sleeve or by thickness variations in the grout annulus. The capacity of connections varied with the square root of the grout strength. Results were compared with recognized empirical formulations. The results indicated that safety factors could be reduced and yet maintain acceptable safety indices. Examination of tested Grouted-connection specimens indicated that the major load-resisting mechanisms are grout compression struts and friction that develops at the grout-steel interface. A simplified analytical model was developed using concrete constitutive relationships, and various geometric and material parameters were investigated. The analytical results indicated that increases in shear-key height or reduction of shear-key spacing may not lead to higher ultimate strength of the connection.
