<p>Dynamic compaction is an effective method for improving silt foundations. In this study, an laboratory experimental setup was developed to simulate stone-block placement and to investigate the settlement characteristics of silt under dynamic compaction. Parametric tests were carried out with varying stone-block shapes (sphere, cube, triangular prism), sizes (14.4–49.2 g), and initial water contents (30–40%) of the silt. Results show that in S1 silt (30% initial water content), at the same settlement depth the 49.2 g block requires vertical loads about 1.7 and 2.6 times those for the 27.7 g and 14.4 g blocks, respectively; for blocks of equal mass, the triangular prism and cube require loads approximately 1.43 and 1.23 times that of the sphere, indicating that both size and shape exert a non-negligible influence on the penetration resistance (i.e., the upward force acting opposite to the block’s downward penetration through the soil). Increasing the initial water content significantly reduces the resistance, highlighting its critical role in settlement behaviors. Based on spherical cavity expansion theory, a penetration resistance model was developed, accurately predicting settlement resistance across diverse geometric conditions. A relative sensitivity analysis of the theoretical model shows co-dominant roles of undrained shear strength and shape (<InlineEquation ID="IEq1"> <EquationSource Format="TEX">${S}_{{S}_{u}}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>S</mi> <msub> <mi>S</mi> <mi>u</mi> </msub> </msub> </math></EquationSource> </InlineEquation> = <InlineEquation ID="IEq2"> <EquationSource Format="TEX">${S}_{\varphi }$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>S</mi> <mi>φ</mi> </msub> </math></EquationSource> </InlineEquation> = 1), both exceeding mass (<InlineEquation ID="IEq3"> <EquationSource Format="TEX">${S}_{m}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>S</mi> <mi>m</mi> </msub> </math></EquationSource> </InlineEquation> = 2/3), thereby providing a mechanistic basis for the design of stone-throwing squeezing in silt foundations.</p>

Dynamic Compaction Resistance Model Considering Stone Block Shape Effects

期刊论文
发表日期：

2025年11月19日

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Xiong Bobo,
Li Hongjun,
Tian Bin,
Chen Bofu,
Zheng Qian,
Li Chen,
Zhang Jingkang

摘要

Dynamic compaction is an effective method for improving silt foundations. In this study, an laboratory experimental setup was developed to simulate stone-block placement and to investigate the settlement characteristics of silt under dynamic compaction. Parametric tests were carried out with varying stone-block shapes (sphere, cube, triangular prism), sizes (14.4–49.2 g), and initial water contents (30–40%) of the silt. Results show that in S1 silt (30% initial water content), at the same settlement depth the 49.2 g block requires vertical loads about 1.7 and 2.6 times those for the 27.7 g and 14.4 g blocks, respectively; for blocks of equal mass, the triangular prism and cube require loads approximately 1.43 and 1.23 times that of the sphere, indicating that both size and shape exert a non-negligible influence on the penetration resistance (i.e., the upward force acting opposite to the block’s downward penetration through the soil). Increasing the initial water content significantly reduces the resistance, highlighting its critical role in settlement behaviors. Based on spherical cavity expansion theory, a penetration resistance model was developed, accurately predicting settlement resistance across diverse geometric conditions. A relative sensitivity analysis of the theoretical model shows co-dominant roles of undrained shear strength and shape ( ${S}_{{S}_{u}}$ $S_{S_{u}}$ = ${S}_{\varphi }$ $S_{φ}$ = 1), both exceeding mass ( ${S}_{m}$ $S_{m}$ = 2/3), thereby providing a mechanistic basis for the design of stone-throwing squeezing in silt foundations.