Effects of gravel content and particle size on abrasivity of sandy gravel mixtures

Wei, Yingjie; Yang, Yiqin; Tao, Mingjiang

doi:10.1016/j.enggeo.2018.06.009

Cited by 36 publications

(3 citation statements)

References 32 publications

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“…Cutter-head rotation speed (rpm) Advances in Civil Engineering e severe wear and tear of EPB machines during tunnelling make it time-consuming, costly, and even dangerous to inspect and maintain the machines while inspection and maintenance of cutting tools in a timely manner are essential to ensure proper performance of EPBS machine [24]. e cutter wear is directly related to cobbles it crushed.…”

Section: Analysis and Discussionmentioning

confidence: 99%

Adaptability of the Cutter‐Head of the Earth Pressure Balance (EPB) Shield Machine in Water‐Rich Sandy and Cobble Strata: A Case Study

Wan

Jin

2020

Advances in Civil Engineering

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Earth Pressure Balance (EPB) shield machines are considered to be the most efficient tunneling method for Metro tunnels due to their adaptability to a great variety of ground conditions, higher construction efficiency, and providing a safer working environment. There are many guidelines available for EPB shield machine selection. However, these guidelines are very general and cannot be used directly for an upcoming project. This paper takes Chengdu Metro Line 6 in China as the engineering background; the studied area is typical of a water-rich sandy and cobble stratum with high content of cobble. Three types of EPBs in the two continuous intervals exhibit significant differences in performance and encounter many difficulties such as wear of the cutter disc and tools, clogging, and severe surface settlement during the operation. These difficulties prevent the construction efficiency, increase the cost of the project, and cause delays in construction period. The causes of these difficulties are summarized by recording and comparing the operational parameters of the three types of EPBs. These parameters that are summarized include the advance rate, total thrust, torque, and the rate of rotation of the cutter-head. In addition, the surface settlements are also compared. The results indicate that the opening rate, maximum opening size, and the opening position of the cutter-head are key factors that affected the geological adaptability of the shield machine in water-rich sandy and cobble strata. Among the three factors, the maximum opening size and opening position are the most important factors influencing the strata adaptability of the cutter-head. To avoid frequent jams of the cutter-head, the maximum torque should be not less than 6,500 kNm. The maximum opening size should not be less than 420 mm × 420 mm. The effect of increasing the central opening of the cutter-head is that large cobbles and boulders can be discharged through the central opening when they cannot be discharged through the opening near the original position of the cobbles and boulders. This paper provides specific guidance on the selection of cutter-head for shield machines in water-rich sandy and cobble strata.

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Section: Analysis and Discussionmentioning

confidence: 99%

Adaptability of the Cutter‐Head of the Earth Pressure Balance (EPB) Shield Machine in Water‐Rich Sandy and Cobble Strata: A Case Study

Wan

Jin

2020

Advances in Civil Engineering

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“…The results indicated that the initial relative density significantly controlled the undrained shear strength and that an increase in the initial relative density led to an amplification of the expansibility, resulting in an increase in the undrained shear strength [6]. Wei et al [7] used a mixture of sand and two different particle sizes of sand gravel, with particle sizes of 5-10 mm and 10-20 mm, respectively. The maximum and minimum densities of the two mixtures gradually increased with increasing sand and gravel content.…”

Section: Introductionmentioning

confidence: 99%

Research on the density of underwater sand and gravel fillings based on geotechnical centrifugal tests

Li,

Wei,

Shen

et al. 2024

IOP Conf. Ser.: Earth Environ. Sci.

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The density of underwater dumping materials plays a major role in cofferdam engineering designs. However, it is difficult to accurately measure the density of underwater dumping materials. This study investigated the influence of particle size distribution of granular materials on the density of underwater filling materials. Considering the underwater dumping project of a hydropower station dam in the Han River as the prototype condition, several underwater dumping density centrifugal tests were conducted on sand gravel and sand mixtures. Based on the CKY200 large-scale geotechnical centrifuge, a single-embankment vertical-blockage underwater filling test device in a centrifuge field was developed. The results demonstrated the relationship between the compactness of the dumping body and the grading of loose particles, depth of dumping, and height of the upper loading. This indicates that the underwater filling material has a higher compactness and can reach a dense state. When the grading is poor, the compactness decreases. The greater the depth of filling, the greater the compactness. When vertical compression was applied to the upper part of the backfill, the compactness of the backfill, particularly in shallow areas, was significantly improved. These results provide insights for the design and construction of underwater dumping water conservation systems.

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“…Soil-rock mixture exists in many natural geological and artificial civil engineering projects [4][5][6]. Because of its different existence conditions and compositions [7,8], many scholars have different research methods and focuses on soil-rock mixtures under different engineering backgrounds. Ding [9] aimed at the soil-rock mixture in the dump site of an open-pit coal mine.…”

Section: Introductionmentioning

confidence: 99%

Study on Permeability of Soil‐Rock Mixture in Water‐Blocking Layer of Open‐Pit Coal Mine Dump Site

Luan

Zhou

Meng

et al. 2020

Advances in Civil Engineering

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Constructing a water-blocking layer in the dump sites of an open-pit coal mine is of great significance to improve the water retention capacity of the reclamation area. The permeability law of the water-blocking layer is costly to be analyzed and researched by means of field tests. In this study, the soil-rock mixture samples similar to the water-blocking layer were prepared, and the rock block proportion (RBP) and hydraulic pressure were adopted as test variables to conduct a permeability test, which provided theoretical support for on-site construction. The results show that when the hydraulic pressure is less than the confining pressure, the permeability increases at a steady rate as the rock block proportion increases. When the hydraulic pressure is close to or equal to the confining pressure, penetrating cracks are easily formed between the soil-rock interfaces of the sample with a higher rock block proportion, resulting in a rapid increase in permeability. With the increase of hydraulic pressure, the migration of the internal fine particles in the sample with a rock block proportion of 40% or less leads to the partial cracks closure, which gradually reduces the permeability. The internal structure of the sample with a rock block proportion more than 40% experiences a process in which the permeability decreases with the crack closure to a significant increase due to the penetrating crack formation. In summary, the soil-rock mixture with about 30% rock block proportion is characterized by suitable permeability and stability, which guarantees the construction cost on-site at the same time. In addition, increasing the rolling times of the truck can increase the compaction of the water-blocking layer and reduce the permeability. The roughness and gradation of the rock blocks can improve the permeability and stability of the water-blocking layer.

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Effects of gravel content and particle size on abrasivity of sandy gravel mixtures

Cited by 36 publications

References 32 publications

Adaptability of the Cutter‐Head of the Earth Pressure Balance (EPB) Shield Machine in Water‐Rich Sandy and Cobble Strata: A Case Study

Adaptability of the Cutter‐Head of the Earth Pressure Balance (EPB) Shield Machine in Water‐Rich Sandy and Cobble Strata: A Case Study

Research on the density of underwater sand and gravel fillings based on geotechnical centrifugal tests

Study on Permeability of Soil‐Rock Mixture in Water‐Blocking Layer of Open‐Pit Coal Mine Dump Site

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