原生各向异性影响下湛江黏土小应变剪切模量特征

刘炳恒; 孔令伟; 舒荣军; 李甜果; 简涛

doi:10.11779/CJGE2021S2005

原生各向异性影响下湛江黏土小应变剪切模量特征 English Version

刘炳恒^{1, 2,},
孔令伟^{1, 2, ,},
舒荣军^{1, 2},
李甜果^{1, 2},
简涛^{1, 2}

1.
中国科学院武汉岩土力学研究所岩土力学与工程国家重点试验室,湖北　武汉　430071
2.
中国科学院大学,北京　100049

基金项目:

国家自然科学基金项目 41877281

详细信息

作者简介:
刘炳恒(1995— ),男,博士研究生,主要从事特殊土的力学特性研究。E-mail: liubingheng17@mails.ucas.ac.cn

通讯作者:
孔令伟, E-mail: lwkong@whrsm.ac.cn

中图分类号: TU43
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出版历程
- 收稿日期: 2021-08-17
- 网络出版日期: 2022-12-05
- 刊出日期: 2021-10-31

Characteristics of small-strain shear modulus of Zhanjiang clay under influence of inherent anisotropy

LIU Bing-heng^{1, 2,},
KONG Ling-wei^{1, 2, ,},
SHU Rong-jun^{1, 2},
LI Tian-guo^{1, 2},
JIAN Tao^{1, 2}

1.
State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China
2.
University of Chinese Academy of Sciences, Beijing 100049, China

摘要

摘要: 为了研究原生各向异性对湛江黏土小应变剪切模量的影响,对 $α$ =0°,22.5°,45°,67.5°,90°方向的原状试样进行了一系列不同围压下的共振柱试验。试验结果表明：在同一围压下,不同 $α$ 试样经孔隙比函数归一化的最大动剪切模量G_max/F(e)与90°方向试样G_max/F(e)的比值K_α随α增大而减小；当围压低于与高于结构屈服应力 $σ_{k}$ 时,同一 $α$ 试样的K_α随围压增大分别呈基本保持恒定与明显减小趋势,即围压低于 $σ_{k}$ 时,围压的增大几乎不影响原生各向异性对G_max的影响,围压高于 $σ_{k}$ 时,围压的增大减弱了原生各向异性对G_max的影响；随围压增大,不同方向试样的G_max/F(e)均呈先增大后减小规律,当围压在 $σ_{k}$ 左右时出现转折；基于不同方向试样G_max/F(e)随围压的变化规律,提出了考虑原生各向异性的G_max演化规律的表征方法。
- 湛江黏土 /
- 原生各向异性 /
- 小应变剪切模量 /
- 共振柱试验 /
- 屈服应力
Abstract: In order to investigate the influence of inherent anisotropy on the small-strain shear modulus of Zhanjiang clay, a series of resonance column tests are carried out on the specimens with α=0°, 22.5°, 45°, 67.5°, and 90° under different confining pressures. The tests results indicate that the ratio of the maximum dynamic shear modulus normalized by the void ratio function G_max/F(e) of the specimens with different α to G_max/F(e) of the specimen with 90° (i.e., K_α) decreases with the increasing α under the same confining pressure. When the confining pressure is lower than or higher than the yield stress σ_k, K_α keeps basically constant or obviously decreases with the increasing confining pressure for the specimen with the same α. When the confining pressure is lower than σ_k, the increase of the confining pressure hardly affects the influence of the inherent anisotropy on G_max. When the confining pressure is higher than σ_k, the increase of the confining pressure weakens the influence of inherent anisotropy on G_max. As the confining pressure increases, G_max/F(e) of specimens in different directions shows the law of first increasing and then decreasing, and a turning point occurs when the confining pressure is around σ_k. Based on the variation law of G_max/F(e) of specimens in different directions with confining pressure, a characterization method of evolution law of G_max considering the inherent anisotropy is proposed.
- Zhanjiang clay /
- inherent anisotropy /
- small-strain shear modulus /
- resonant column test /
- yield stress

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图 1 试样示意图与试验设备

Figure 1. Schematic diagram of specimens and test apparatus

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图 2 不同方向试样剪切模量G与剪应变 $γ$ 关系

Figure 2. Relationship between shear modulus G and shear strain $γ$ for specimens in different directions

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图 3 不同方向试样G_max/F(e)与围压σ₃的关系

Figure 3. Relationship between G_max /F(e) and confining pressure σ₃ for specimens in different directions

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图 4 不同方向试样K_α与围压σ₃的关系

Figure 4. Relationship between K_α and confining pressure σ₃ for specimens in different directions

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图 5 不同方向试样的G_max/F(e)与固结围压lgσ₃关系曲线

Figure 5. Curves of G_max/F(e) and confining pressure lgσ₃ of specimens in different directions

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图 6 拟合参数A,k_r和λ与试样方向的关系

Figure 6. Relationship between fitting parameters A, k_r and λ with directions of specimens

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表 1 湛江黏土平均物理力学性质指标与颗粒组成

Table 1 Physical and mechanical indexes and particle composition of Zhanjiang clay

重度γ/(kN·m^-3)	含水率w/%	孔隙比e	渗透系数K/(cm·s^-1)	液限w_L/%	塑限w_P/%	塑性指数I_P	结构屈服应力σ_k/kPa	无侧限抗压强度/kPa	灵敏度S_t	颗粒组成/%
重度γ/(kN·m^-3)	含水率w/%	孔隙比e	渗透系数K/(cm·s^-1)	液限w_L/%	塑限w_P/%	塑性指数I_P	结构屈服应力σ_k/kPa	无侧限抗压强度/kPa	灵敏度S_t	>0.05/mm	0.005~0.05/mm	0.002~0.005/mm	<0.002/mm
17.1	52.98	1.44	2.73×10⁻⁸	59.6	28.1	31.5	400	143.5	7.2	8.2	39.5	20.7	31.6

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表 2 不同方向试样拟合参数

Table 2 Fitting parameters of specimens in different directions

α	A/MPa	B	n	k_r	η	λ	R²
0^°	39.92489	0.16678	0.54309	0.35092	0.56433	6.42998	0.99251
22.5^°	37.89951	0.15999	0.58264	0.35462	0.56426	6.37147	0.99075
45^°	33.76328	0.15168	0.54642	0.37740	0.55402	6.38473	0.99432
67.5^°	31.15476	0.15761	0.56254	0.42499	0.60889	6.07737	0.99727
90^°	29.75422	0.15743	0.56067	0.44448	0.57750	6.05669	0.99835

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参考文献(4)

[1]	SIMPSON B, ATKINSON J H, JOVIČIĆ V. The influence of anisotropy on calculations of ground settlements above tunnels[C]//International Symposium on Geotechnical Aspects of Underground Construction in Soft Ground, London, England, 1996: 591-594.
[2]	JOVIČIĆ V, COOP M R. The measurement of stiffness anisotropy in clays with bender element tests in the triaxial apparatus[J]. Geotechnical Testing Journal, 1998, 21(1): 3-10. doi: 10.1520/GTJ10419J
[3]	吴宏伟, 李青, 刘国彬. 利用弯曲元测量上海原状软黏土各向异性剪切模量的试验研究[J]. 岩土工程学报, 2013, 35(1): 150-156. https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201301016.htm NG C W W, LI Qing, LIU Guo-bin. Measurements of small-strain inherent stiffness anisotropy of intact Shanghai soft clay using bender elements[J]. Chinese Journal of Geotechnical Engineering, 2013, 35(1): 150-156. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-YTGC201301016.htm
[4]	孔令伟, 臧濛, 郭爱国. 湛江黏土动剪切模量的结构损伤效应与定量表征[J]. 岩土工程学报, 2017, 39(12): 2149-2157. doi: 10.11779/CJGE201712001 KONG Ling-wei, ZANG Meng, GUO Ai-guo. Structural damage effect on dynamic shear modulus of Zhanjiang clay and quantitative characterization[J]. Chinese Journal of Geotechnical Engineering, 2017, 39(12): 2149-2157. (in Chinese) doi: 10.11779/CJGE201712001