Field Rebound and Recompression Curve of Soft Clay

Li, Zhuofeng; Chen, Yunmin; Zhou, Yan‐Guo; Bian, Xuecheng

doi:10.1520/gtj20190242

Cited by 6 publications

(9 citation statements)

References 41 publications

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“…The uniformity of the samples by the static compression method was relatively poor, and there was residual stress during the static pressing, resulting in a lower shear strength of the sample. It is also in accordance with the current research [25,26] that the sample preparation process produces structural differences and residual stresses, and affects its strength.…”

Section: Discussionsupporting

confidence: 89%

“…After the CU test, the main peak of the pore size of the sample has a significant left shift relative to that before the test, and the pore size distribution shows a good consistency at the main peak. Current studies [25,26] showed that the difference mainly caused by the internal structure of the soil and the internal stresses. In the test, the pore structure significantly changes for the sample prepared by the static compression method, indicating that under the high dry density, the sample is not completely uniform before the test, and there is still a large residual stress inside.…”

Section: Dynamic Triaxial Test Schemementioning

confidence: 99%

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Study on the Influence Mechanism of Sample Preparation Method on the Shear Strength of Silty Soil

Qian²,

Xuan

et al. 2023

Sustainability

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During the compaction of silty soil subgrade, different filling methods are adopted, which will significantly impact the subgrade performance, but few studies have been applied to quantify this influence. To explore the influence mechanism of dry density and sample preparation method (compaction and static compression method) on the shear strength of silty soil, the consolidated undrained shear test (CU test), dynamic triaxial test, and nuclear magnetic resonance microscopic test on silty soil were carried out in this study. The test results show that the shear strength of the sample is positively correlated with the dry density. The influence of the sample preparation method on shear strength is mainly reflected in the cohesion. The pore size distributions obtained by different sample preparation methods had smaller differences before the CU test. However, significant differences were observed after the CU test, indicating that the influence of the sample preparation method on the shear strength of the sample is not on the initial pore distribution but on the residual stress and overall uniformity. The dynamic triaxial tests show that a differential settlement may occur when multiple sample preparation (soil-filling method in subgrade practice) methods are adopted.

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Section: Discussionsupporting

confidence: 89%

Section: Dynamic Triaxial Test Schemementioning

confidence: 99%

Study on the Influence Mechanism of Sample Preparation Method on the Shear Strength of Silty Soil

Qian²,

Xuan

et al. 2023

Sustainability

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“…In this section, based on the previously proposed in-situ rebound-recompression curve [25], we make corrections to the required void ratio and rebound index for the calculation of excavation rebound. By referencing the traditional method for calculating foundation settlement and treating the self-weight stress of the excavated soil as unloading additional stress, we propose a calculation method for excavation rebound based on RRM.…”

Section: The Rebound Calculation Methods Based On Rrm Methodsmentioning

confidence: 99%

“…In reality, soil samples undergo stress relief and disturbance during the collection and preparation process before testing, thereby generating discrepancies between the one-dimensional consolidation compression curve observed in the laboratory and that observed in the field. To address this issue, Li et al [25] proposed a correction method known as the Rebound-recompression method (RRM), which seeks to obtain the in-situ soil parameters for field rebound-recompression curves. The use of RRM enables the utilization of in-situ soil parameters for the calculation of soil rebound resulting from excavation, resulting in more realistic outcomes relative to those generated by laboratory-disturbed soil parameters.…”

Section: Introductionmentioning

confidence: 99%

Rebound Calculation for Deep Excavation in Soft Soil Based on Rebound-Recompression Method

Zhu

et al. 2023

Sustainability

Self Cite

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The excavation-induced stress relief and inward movement of the retaining wall will result in soil rebound deformation at the bottom of the excavation, adversely affecting nearby existing tunnels and foundation piles. Various existing methods for calculating the excavation rebound rely on rebound parameters and void ratio obtained from laboratory tests, with considering the effects of sampling, specimen preparation and laboratory procedures on the rebound parameters. As a result, a novel method is proposed in this article for calculating excavation rebound based on rebound-recompression method (RRM). This method first modifies initial void ratio (e0) and laboratory recompression index (CLR) used in traditional methods (TM) for calculation, based on field rebound and recompression curve proposed by the RRM, to in situ void ratio (ev0) and field recompression index (CFR). Then, the final rebound at the bottom of the excavation is calculated using a layered summation method. In addition, through two engineering examples, the proposed method is compared with existing calculation methods and measurements, demonstrating that this method is easy of calculate, yields reliable results, and can accurately predict the final soil rebound at the bottom of the excavation.

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“…In obtaining the soil sample and preparing it for the laboratory test, soil stress release and disturbance occur simultaneously, resulting in differences between the laboratory compression curves and field compression curves [9,[23][24][25]. To overcome this problem, Li et al [26] proposed a modified approach, the rebound-recompression method (RRM), to obtain the field rebound-recompression curve that can reflect the actual situation more accurately.…”

Section: Introductionmentioning

confidence: 99%

Calculation of Column Pile Heave in Deep Excavation Based on the Rebound–Recompression Method

Yang,

Chen,

2024

Buildings

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Excessive column pile heave may result in engineering disasters such as instability of retaining structures and cracking of existing engineering piles in deep excavations. However, factors such as support weight, changeable support restraint resistance, and soil disturbance at the bottom of the excavation are often ignored or simplified in existing calculation methods but have a significant impact on the calculation results. Based on field soil parameters obtained by the rebound–recompression method, a semi-analytical method is proposed for estimating column pile heaves in a deep excavation. This method considers the influence of soil disturbance, the weight of the retaining structure, and the changeable horizontal support restraint, making the calculation result more consistent with the realistic situation. This method can also be used to analyze load transfer between the pile and the surrounding soil. The rationality of this proposed calculation method is verified by measured data, where the variation in pile stress state during deep excavation is analyzed. Finally, a parametric study is conducted, and the results show that the excavation size and the excavation depth have a great influence. However, the heave is hardly affected by the value of the limit relative displacement. The use of long piles with small diameter and the method of small block excavation are effective means to control the column pile heave. When the excavation area is large or the effective pile length is short, the factor of the position of the column pile cannot be ignored.

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Field Rebound and Recompression Curve of Soft Clay

Cited by 6 publications

References 41 publications

Study on the Influence Mechanism of Sample Preparation Method on the Shear Strength of Silty Soil

Study on the Influence Mechanism of Sample Preparation Method on the Shear Strength of Silty Soil

Rebound Calculation for Deep Excavation in Soft Soil Based on Rebound-Recompression Method

Calculation of Column Pile Heave in Deep Excavation Based on the Rebound–Recompression Method

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