The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Chen Feng - One of the best experts on this subject based on the ideXlab platform.
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Review on Dynamic Modulus of Coarse-grained Soil Filling for High-speed Railway Subgrade
Transportation Geotechnics, 2021Co-Authors: De-gou Cai, Yao Junkai, Wei Shaowei, Hong-ye Yan, Chen FengAbstract:Abstract The attenuation of dynamic modulus of coarse-grained soil filling with the increase of the strain should be considered in the refined design of the high-speed railway subgrade. On the basis of a large number of past investigations by other researchers on dynamic modulus of coarse-grained soil at home and abroad, this paper analyzes the mechanical properties of coarse-grained soil filling in high-speed railway subgrade under cyclic train load, with characteristics of small confining pressure, high density, low water content and weak structural property. By summarizing the empirical models of dynamic modulus and the range of attenuation curves, a method to determine the value of dynamic modulus of coarse-grained soil filling in high-speed railway subgrade has been proposed, with the reasonable range of the working dynamic modulus ratio being discussed. According to the measured dynamic deformation of ballastless track subgrade for a number of high-speed railway lines in China, the average working dynamic modulus of Graded Gravel in the surface layer and class A&B filling material in the bottom layer of the subgrade are 0.60∼0.80 times and 0.73∼0.90 times of the maximum modulus, respectively.
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railway soft soil foundation light soil roadbed structure
2017Co-Authors: Zhang Qianli, Li Zhongguo, Yan Hongye, Cheng Yuanshui, Cheng Aijun, Du Xiaoyan, Wang Lijun, Chen Feng, Yan XinAbstract:The utility model relates to railway soft soil foundation light soil roadbed structure, it fills out the bottom surface in the ground grooving to trading, sets up precast tubular pile according to designing the interval, and the pile bolck bassets, fill out the bottom surface and set up the waterproof layer, the cast -in -place bubble light soil of layering on the waterproof layer, vertical separation 2 on the bubble light soil simultaneously trading 3 one deck galvanized wire mesh is laid to rice. This bubble light soil below ground part for trapezoidal, use every layer on top as the step on ground. It is trapezoidal domatic to fill filler formation around this cascaded bubble light soil, at the making Graded Gravel layer of the superiors of bubble light soil. The utility model discloses having reduced the imposed load on the ground, having made the ground reach more easily and bear and warp the requirement, reduced the degree of difficulty that deep soft soil foundation handled, it is convenient to be under construction, and economic performance is good, the difficult railway roadbed structure that produces post -construction settlement to be suitable for the practicality more.
Emmanuel Javelaud - One of the best experts on this subject based on the ideXlab platform.
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Assessment of ground compaction using multi-channel analysis of surface wave data and cone penetration tests
Near Surface Geophysics, 2013Co-Authors: Adnand Bitri, Kévin Samyn, Stéphane Brûlé, Emmanuel JavelaudAbstract:The construction of a new industrial and commercial area in 2009 at the Givors' former glass factory area in France involved heavy dynamic compaction work. For the purpose of founding the new buildings, it was necessary to improve the ground mechanical properties of 7-15 m of well-Graded Gravel backfill lying on geotechnical bedrock. In order to assess the quality and depth of ground compaction, cone penetration tests are often performed before and after compaction. The method is intrusive and a one-location test. It requires a substantial amount of time to evaluate a large area and evaluation quality is quite dependent on the operation technique and soil type. In this paper, the quality and extent of ground compaction were evaluated using results from the in situ Multi- Channel Analysis of Surface Waves (MASW) seismic method and cone penetration tests (CPT). MASW tests were used to determine shear-wave velocity (Vs) profiles before and after compaction and CPT tests were adopted to determine the correlation between Vs and the measured penetration resistance (qc) improvement along profiles. The results of this study show the effectiveness of surface waves for the evaluation of compaction performance and demonstrate the potential of this technique to engineering and environmental problems.
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Assessment of ground compaction using multi-channel analysis of surface wave data and cone penetration tests
Near Surface Geophysics, 2013Co-Authors: Adnand Bitri, Kévin Samyn, Stéphane Brûlé, Emmanuel JavelaudAbstract:International audienceThe construction of a new industrial and commercial area in 2009 at the Givors' former glass factory area in France involved heavy dynamic compaction work. For the purpose of founding the new buildings, it was necessary to improve the ground mechanical properties of 7-15 m of well-Graded Gravel backfill lying on geotechnical bedrock. In order to assess the quality and depth of ground compaction, cone penetration tests are often performed before and after compaction. The method is intrusive and a one-location test. It requires a substantial amount of time to evaluate a large area and evaluation quality is quite dependent on the operation technique and soil type. In this paper, the quality and extent of ground compaction were evaluated using results from the in situ Multi- Channel Analysis of Surface Waves (MASW) seismic method and cone penetration tests (CPT). MASW tests were used to determine shear-wave velocity (Vs) profiles before and after compaction and CPT tests were adopted to determine the correlation between Vs and the measured penetration resistance (qc) improvement along profiles. The results of this study show the effectiveness of surface waves for the evaluation of compaction performance and demonstrate the potential of this technique to engineering and environmental problems
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Assessment of Ground Compaction using Multi-channel Analysis of Surface Wave Data and Cone Penetration Tests
Near Surface Geoscience 2012 – 18th European Meeting of Environmental and Engineering Geophysics, 2012Co-Authors: Kévin Samyn, Adnand Bitri, Stéphane Brûlé, Emmanuel JavelaudAbstract:The construction of a new industrial and commercial area has involved heavy dynamic compaction work. The objective was to improve the ground mechanical properties of 7 to 15 m of well-Graded Gravel backfills lying on the geotechnical bedrock. To assess the quality and depth of ground compaction, cone penetration tests are often performed before and after the compaction. The method is intrusive, covers only one location at a time and requires a substantial amount of time to evaluate a large area. The evaluation quality is very dependent on the operational technique and soil type. In this paper, the quality and extent of ground compaction were evaluated using the results from in situ Multi-Channel Analysis of Surface Waves (MASW) seismic method and cone penetration tests (CPTs). The MASW tests were used to determine the shear wave velocity (Vs) profiles before and after the compaction, and the CPTs were utilised to determine the correlation between the Vs and the measured penetration resistance (qc) improvement along the profiles. The results of this study demonstrate both the effectiveness of using surface waves for the evaluation of compaction performance and the potential application of this technique to engineering and environmental problems.
De-gou Cai - One of the best experts on this subject based on the ideXlab platform.
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Review on Dynamic Modulus of Coarse-grained Soil Filling for High-speed Railway Subgrade
Transportation Geotechnics, 2021Co-Authors: De-gou Cai, Yao Junkai, Wei Shaowei, Hong-ye Yan, Chen FengAbstract:Abstract The attenuation of dynamic modulus of coarse-grained soil filling with the increase of the strain should be considered in the refined design of the high-speed railway subgrade. On the basis of a large number of past investigations by other researchers on dynamic modulus of coarse-grained soil at home and abroad, this paper analyzes the mechanical properties of coarse-grained soil filling in high-speed railway subgrade under cyclic train load, with characteristics of small confining pressure, high density, low water content and weak structural property. By summarizing the empirical models of dynamic modulus and the range of attenuation curves, a method to determine the value of dynamic modulus of coarse-grained soil filling in high-speed railway subgrade has been proposed, with the reasonable range of the working dynamic modulus ratio being discussed. According to the measured dynamic deformation of ballastless track subgrade for a number of high-speed railway lines in China, the average working dynamic modulus of Graded Gravel in the surface layer and class A&B filling material in the bottom layer of the subgrade are 0.60∼0.80 times and 0.73∼0.90 times of the maximum modulus, respectively.
Brett C. Eaton - One of the best experts on this subject based on the ideXlab platform.
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Mechanisms for avulsion on alluvial fans: insights from high‐frequency topographic data
Earth Surface Processes and Landforms, 2021Co-Authors: Anya Leenman, Brett C. EatonAbstract:Avulsion is a key process in building alluvial fans, but it is also a formidable natural hazard. Based on laboratory experiments monitored with novel high-frequency photogrammetry, we present a new model for avulsion on widely Graded Gravel fans. Previous experimental studies of alluvial fans have suggested that avulsion occurs in a periodic autogenic cycle, that is thought to be mediated by the gradient of the fan and fan-channel. However, these studies measured gradients at low spatial or temporal resolutions, which capture temporally or spatially averaged topographic evolution. Here, we present high-resolution (1 mm), high-frequency (1-minute) topographic data and orthophotos from an alluvial fan experiment. Avulsions in the experiment were rapid and, in contrast to some previous experimental studies, avulsion occurrence was aperiodic. Moreover, we found little evidence of the back-filling observed at coarser temporal and spatial resolutions. Our observations suggest that avulsion is disproportionately affected by sediment accumulation in the channel, particularly around larger, less mobile grains. Such in-channel deposition can cause channel shifting that interrupts the autogenic avulsion cycle, so that avulsions are aperiodic and their timing is more difficult to predict.
Tengfei Wang - One of the best experts on this subject based on the ideXlab platform.
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evaluating frost heave susceptibility of well Graded Gravel for hsr subgrade based on orthogonal array testing
Transportation geotechnics, 2019Co-Authors: Qiang Luo, Tengfei WangAbstract:Abstract Well-Graded Gravels are usually considered non-frost-susceptible, which appears to be a fair assumption in accordance with universally recognized frost criterions; However, their frost heave susceptibility is affected by the unavoidable presence of fines (passing through No. 200 sieve, 0.075 mm) and water when used as backfills for high-speed rail (HSR) subgrade. In practice, non-negligible frost heave would occur within Gravels throughout a severe winter, causing great difficulties for operation and maintenance of high-speed trains which tolerates a maximum heave amount of 5 mm. This paper introduces a series of unidirectional freezing tests performed on Gravel soils that rely on an orthogonal array, and the frost heave properties of tested material were obtained under the combined effect of moisture content, fines content, dry density, and cooling temperature. The average heaving ratio (AHR), an indication of frost heave susceptibility, was estimated by multivariate regression analysis using a stepwise approach. The results suggest that moisture content exerts the greatest influence on average heaving ratio of well-Graded Gravels, followed by dry density, fines content, and cooling temperature. In addition, whether the dry density is positively or negatively related to an average heaving ratio depends on the levels of fines content and cooling temperature. A statistical model considering the interaction between factors is proposed to predict the average heaving ratio and to evaluate the frost heave susceptibility of well-Graded Gravels further.
