ORCID Profile
0000-0002-5151-4402
Current Organisation
Central South University
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Publisher: Springer Science and Business Media LLC
Date: 21-04-2016
Publisher: Springer Science and Business Media LLC
Date: 14-11-2018
Publisher: Canadian Science Publishing
Date: 06-2021
Abstract: This paper presents results of scaled physical model tests performed to measure the reaction developing on a rigid pipe buried in dry sand when the pipe is subjected to vertical downwards movement relative to its surrounding soil. The aim of this experimental study is to evaluate the efficacy of methods used to determine the properties of vertical bearing springs, an integral part of beam-on-nonlinear Winkler spring models used for the analysis of buried pipelines subjected to permanent ground displacements. We show that bearing capacity formulas used in practice to estimate the ultimate reaction developing on buried pipes may provide reasonably accurate estimates, provided that they are used together with sand friction angle values that account for the fact that granular materials do not obey an associative flow rule, and with bearing capacity factors compatible with the mode of sand failure observed in the tests. We also provide evidence suggesting that laying pipes in loose sand backfills does not have a beneficial effect on the reaction developing on the pipe, compared to medium dense sand, and we recommend against using loose sand material properties for the estimation of the properties of vertical bearing springs.
Publisher: Springer Science and Business Media LLC
Date: 12-10-2022
DOI: 10.1007/S11440-022-01710-6
Abstract: This paper presents an experimental study on quantifying the effects of soil suction on the resistance offered by compacted unsaturated backfills to uplift of buried steel pipes and identifying the mechanisms that contribute to increased resistance compared to similar pipes buried in dry sand. This is achieved by means of 1-g physical model experiments, with the pipe buried in sandy loam–Kaolin soil beds of varying water content (suction), compacted to the same dry unit weight. The main experiments are supplemented by benchmarking experiments performed in dry sand of similar grain size distribution, as well as in compacted soil beds inundated with water to achieve conditions close to full saturation. The experiments are supported by a detailed characterisation study of compacted sandy loam–Kaolin mixtures and mini-CPT tests performed to evaluate the uniformity of the soil beds. Measurements of the reaction developing on the pipe as function of its uplift displacement are co-evaluated together with images of the failure mechanisms obtained using particle image velocimetry and continuous measurements of soil matrix suction. We conclude with a simplified method to predict the peak reaction to pipe uplift that allows considering the contribution of suction and the tensile–shear failure mechanism observed during the experiments.
Publisher: Elsevier BV
Date: 07-2021
Publisher: Elsevier BV
Date: 2018
Publisher: Thomas Telford Ltd.
Date: 09-2022
Abstract: This paper presents an air pluviation system, developed to facilitate 1g physical model tests in granular soils. The deposition process is fully automated and requires minimal input from the operator, thereby significantly reducing the time required to deposit large volumes of granular material, improving the uniformity of the prepared specimens and the reliability of test results. The components comprising the pluviation system have been calibrated to produce loose-to-very dense sand beds, of relative density that ranges between D r = 7% and 100% of the maximum density achieved with the procedures described in the pertinent standards. The testing chamber where sand is deposited is instrumented with an array of pressure sensors, and the rig is equipped with a miniature cone penetration testing (mini-CPT) device. Measurements from the earth pressure sensors and cone tip resistance profiles are used to evaluate how friction at the sand–chamber interfaces affects the distribution of geostatic stresses inside the chamber, the uniformity of sand beds and boundary effects during deposition and during mini-CPT testing. The air pluviation system allows preparing layered sand profiles by adjusting the deposition parameters on the fly, and this feature is demonstrated through the analysis of mini-CPT tests performed in layered sand beds.
Publisher: Public Library of Science (PLoS)
Date: 12-03-2019
Publisher: Trans Tech Publications, Ltd.
Date: 09-2014
DOI: 10.4028/WWW.SCIENTIFIC.NET/AMR.1030-1032.908
Abstract: The combination of PHC pile (prestressed concrete pile) with geogrid to reinforce the foundation has been widely used in high-speed railway, and the response of dynamic stress under the high-speed train is worth studying. By using Midas/GTS NX software to establish a 3-D model of pile-net composite foundation in one section of Hangzhou - Shenzhen line, the influence of pile-net composite foundation generated by high-speed train is studied. Moreover, this paper also studies the distribution and propagation of dynamic stress generated by train load in soft soil area. The results show that the dynamic stress reducing quickly in the embankment structure and the time –history curve of the dynamic stress behaves differently along the depth. With the depth increasing, there is phenomenon of peak superposition in the time-history curve of the vertical dynamic stress. In the meanwhile, the PHC pile is the main structure to propagate and sustain the dynamic stress in soft soil area, and with the tendency of ‘large in the middle, small on both ends’.
Publisher: Springer Science and Business Media LLC
Date: 2019
Publisher: Canadian Science Publishing
Date: 10-2020
Abstract: This paper presents results of a series of experiments modelling uplift and lateral drag of a rigid pipe buried in dry sand. The main aim of these tests is to document the gradual transition from shallow to a deep sand failure mechanism as the pipe embedment depth increases, identify which parameters affect this transition, and determine experimentally the critical embedment depth, beyond which the normalized reaction acting on the pipe remains constant with increasing pipe embedment. Measurements of the reaction as a function of the relative sand–pipe movement and analysis of images captured during the tests with the particle image velocimetry method suggest that the critical embedment depth depends on sand density, but not on the direction of pipe movement. Outcomes of this study contribute to identifying the limits of applicability of simplified methods used to determine the peak reaction on pipes subjected to ground movements and the estimation of rational parameters for the analysis of deeply buried pipes with beam-on-nonlinear Winkler foundation models.
No related grants have been discovered for Wu Jinbiao.