Experimental Study on Maximum Dynamic Shear Modulus of Yangtze River Floodplain Overconsolidated Soft Soil
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摘要: 为探究长江漫滩相超固结软土最大动剪切模量Gmax变化特征,利用弯曲元对原状长江漫滩相软土开展了系列试验研究,探讨了不同超固结比HOCR、初始有效固结围压σ' 3c及孔隙比e对漫滩相软土Gmax的影响规律。试验结果表明,当σ' 3c和HOCR均相同时,Gmax随e的增大而减小;HOCR的增大会导致Gmax随e的衰减速度逐渐降低,而σ' 3c的增大不会引起Gmax衰减速度的变化。孔隙归准化最大剪切模量Gmax/F(e)随归准化初始有效围压σ' c0/Pa的增大而增加,但其增长速率逐渐降低,Gmax/F(e)与σ' 3c/Pa呈幂函数关系。基于回归分析,提出了合理表征具有不同超固结状态、初始应力条件及密实程度的长江漫滩相软土Gmax预测方法,并通过独立试验验证了该方法的有效性。Abstract: To investigate the maximum dynamic shear modulus (Gmax) of overconsolidated soft soil from the Yangtze River floodplain, a series of bender element tests were conducted. These tests explored the effects of the overconsolidation ratio (HOCR), initial effective confining pressure (σ' 3c), and void ratio (e) on Gmax. The results show that Gmax decreases as the void ratio (e) increases, given constant values of σ' 3c and HOCR. Furthermore, increasing the HOCR reduces the decay rate of Gmax, while this decay rate remains relatively insensitive to changes in σ' 3c. The void ratio-normalized maximum shear modulus, Gmax/F(e), was found to increase with rising stress-normalized initial effective confining pressure (σ' 3c/Pa). However, the rate of increase exhibited a declining trend. Notably, Gmax/F(e) follows a unique power-law relationship with σ' 3c/Pa, indicating a consistent pattern across different stress conditions. Through regression analysis, a predictive method for estimating Gmax in Yangtze River floodplain soft soils with varying overconsolidation states, initial stress conditions, and degrees of compaction has been developed. The accuracy and reliability of this method have been verified through independent experimental testing, confirming its effectiveness in characterizing the dynamic shear properties of soft soils in this region.
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表 1 试验土样及基本物理性质
Table 1. Basic physical properties of test soil samples
编号 H/m ρ/(g·cm−3) w/% e Ip/% σ' 3c/kPa HOCR 编号 H/m ρ/(g·cm−3) w/% e Ip/% σ' 3c/kPa HOCR A1 8.7~8.9 1.39 39.32 0.95 16.3 50 1 C1 15.4~15.6 1.40 42.41 0.95 17.1 120 1 A2 6.8~7.0 1.27 40.11 1.1 17.2 50 1 C2 17.1~17.3 1.31 38.42 1.04 16.2 120 1 A3 6.3~6.5 1.31 41.08 1.04 17.4 50 1 C3 16.1~16.3 1.29 41.38 1.08 16.3 120 1 A4 8.3~8.5 1.27 40.14 1.13 16.9 50 1 C4 15.3~15.5 1.27 39.33 1.13 17.8 120 1 A5 8.2~8.4 1.33 38.81 1.03 16.8 50 2 C5 16.2~16.4 1.27 38.31 1.15 16.3 120 1 A6 7.7~7.9 1.29 42.61 1.08 16.8 50 2 C6 15.7~15.9 1.32 39.87 1.03 16.9 120 2 A7 9.2~9.4 1.26 41.43 1.12 17.4 50 2 C7 15.1~15.3 1.29 40.24 1.08 17.1 120 2 A8 7.4~7.7 1.26 40.43 1.15 17 50 2 C8 15.8~16.0 1.28 36.93 1.11 15.4 120 2 A9 7.3~7.5 1.30 39.55 1.09 17.5 50 3 C9 16.5~16.7 1.25 41.66 1.13 17.2 120 2 A10 8.3~8.5 1.33 40.84 1.03 17.2 50 3 C10 16.3~16.5 1.32 37.17 1.03 15.9 120 3 A11 7.8~8.0 1.26 41.45 1.13 17.3 50 3 C11 15.2~15.4 1.30 39.24 1.08 14.8 120 3 A12 5.4~5.6 1.39 42.94 0.96 16.8 50 3 C12 15.6~15.8 1.28 40.92 1.12 17.5 120 3 B1 13.7~13.9 1.36 40.06 0.97 17.4 85 1 C13 15.7~15.9 1.26 39.82 1.14 16.4 120 3 B2 14.5~14.7 1.33 39.91 1.04 16.3 85 1 D1 21.1~21.3 1.35 41.43 0.99 17.5 150 1 B3 14.5~14.7 1.29 40.5 1.09 17.6 85 1 D2 22.3~22.5 1.33 40.92 1.05 16.5 150 1 B4 12.5~12.7 1.25 40.26 1.14 16.5 85 1 D3 23.1~23.3 1.28 41.59 1.11 17.1 150 1 B5 14.1~14.3 1.26 39.59 1.16 16.9 85 1 D4 23.8~24.0 1.26 40.92 1.15 17.5 150 1 B6 14.3~14.5 1.34 40.42 1.01 16.5 85 2 D5 21.6~21.8 1.23 41.66 1.18 17 150 2 B7 13.1~13.3 1.30 40.14 1.08 16.7 85 2 D6 22.5~22.7 1.27 39.45 1.11 17.1 150 2 B8 14.8~15.0 1.31 41.05 1.09 17 85 2 D7 23.3~23.5 1.30 41.11 1.05 17.3 150 2 B9 14.7~14.9 1.25 41.27 1.14 17.2 85 2 D8 23.8~24.0 1.38 38.23 0.98 16.4 150 2 B10 13.8~14.0 1.19 40.6 1.26 16.7 85 2 D9 21.9~22.1 1.37 39.83 0.95 16.6 150 3 B11 14.5~14.7 1.35 38.87 1.02 15.1 85 3 D10 22.9~23.1 1.33 40.14 1.03 17.8 150 3 B12 13.1~13.3 1.30 38.43 1.09 17.2 85 3 D11 23.4~23.6 1.28 39.82 1.10 17.1 150 3 B13 13.5~13.7 1.27 40.21 1.12 16.7 85 3 D12 24.6~24.8 1.25 38.92 1.16 17.4 150 3 B14 14.9~15.1 1.24 41.7 1.14 16.9 85 3 表 2 独立验证试验工况
Table 2. Basic physical properties of test soil samples
编号 H/m ρ/(g·cm−3) w/% e Ip/% σ' 3c/kPa HOCR Gmax E1 8.7~8.9 1.35 40.32 0.96 16.3 50 1.5 21.65 E2 7.7~7.9 1.26 39.11 1.13 17.2 50 2.5 37.64 E3 12.3~12.5 1.30 42.08 1.05 17.4 85 1.5 32.37 E4 13.3~13.5 1.28 39.14 1.12 16.9 85 2.5 40.63 E5 15.2~15.4 1.32 40.81 1.04 16.8 120 1.5 43.39 E6 15.7~15.9 1.28 43.61 1.05 16.8 120 2.5 45.34 -
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