深海硅藻土强度特性及其对光缆沉陷的影响

谢雅囡; 裴会敏; 王栋; 孙永福; 高伟; 胥维坤

doi:10.11779/CJGE20220800

深海硅藻土强度特性及其对光缆沉陷的影响 English Version

1.
中国海洋大学海洋环境与生态教育部重点实验室, 山东青岛 266100
2.
国家深海基地管理中心, 山东青岛 266237

基金项目:

国家自然科学基金项目 42025702

国家自然科学基金项目 U1806230

详细信息

作者简介:
谢雅囡(1998—)，女，博士研究生，主要从事海洋岩土工程方面的研究工作。E-mail: xieyanan@stu.ouc.edu.cn

通讯作者:
孙永福, E-mail: sunyongfu@ndsc.org.cn

中图分类号: TU431
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出版历程
- 收稿日期: 2022-06-26
- 网络出版日期: 2023-02-26
- 刊出日期: 2023-09-30

Strength characteristics of deep-sea diatomite and their influences on settlement of optical cables

1.
Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China
2.
National Deep Sea Center, Qingdao 266237, China

摘要

摘要: 深海硅藻土是一种深海生物硅藻成因的硅质软泥，其典型特征是含水率大、强度低。采用流体力学中的流变模型描述硅藻土，并通过流变试验建立起不排水抗剪强度与剪应变速率之间的关系，试验中还发现硅藻土具有一定的灵敏度。当光缆铺设在深海硅藻土上时，必须合理估计光缆的沉陷。采用大变形有限元方法模拟光缆与硅藻土的相互作用，其中引入考虑速率效应与应变软化的公式。基于数值结果，讨论影响光缆贯入阻力的因素和不同灵敏度下的光缆沉陷量，给出了两种典型铠装光缆在硅藻土中的沉陷量范围。
- 硅藻土 /
- 应变率效应 /
- 灵敏度 /
- 有限元 /
- 沉陷
Abstract: The deep-sea diatomite is a kind of siliceous ooze of deep-sea biodiatom origin, which is featured with very high water content and low strength. A rheological model in fluid mechanics is used to describe the strength of diatomite, and the relationship between the undrained shear strength of diatomite and the shear strain rate is established through the rheological tests. It is found in the tests that the sensitivity of diatomite cannot be ignored. When the optical cables are laid on the deep-sea diatomite, the cable settlement needs to be estimated reasonably. The interaction between the optical cables and the diatomite is explored using the large-deformation finite element approach, in which the effects of strain rate and strain softening are considered. Based on the numerical results, the factors affecting the penetration resistance of cables are discussed, while the cable settlements against a variety of sensitivities are investigated. The settlement ranges of two typical armored optical cables on diatomite are determined.
- diatomite /
- strain-rate dependency /
- soil sensitivity /
- finite element /
- settlement

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图 1 油气管线贯入阻力模型

Figure 1. Model for penetration resistance of oil and gas pipeline

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图 2 硅藻土土样

Figure 2. Diatomite samples

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图 3 深海硅藻土扫描电镜图像

Figure 3. SEM images of deep-sea diatomite

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图 4 部分扰动土在不同剪应变速率下的剪应力

Figure 4. Shear stresses of partially disturbed soils at different shear strain rates

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图 5 完全重塑土在不同剪应变速率下的剪应力

Figure 5. Shear stresses of remolded soils at different shear strain rates

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图 6 部分扰动土和完全重塑土不排水抗剪强度对比

Figure 6. Comparison of undrained shear strengths between partially disturbed and remolded samples

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图 7 管线在黏土中的贯入阻力对比

Figure 7. Comparison of pipeline penetration resistances in clays

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图 8 光缆沉陷过程中土体破坏模式演变

Figure 8. Evolution of soil failure during settlement of optical cable

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图 9 不同s_u0时归一化后的贯入阻力-位移曲线

Figure 9. Normalized penetration resistance-displacement curves for different s_u0

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图 10 应变速率对光缆沉陷的影响

Figure 10. Influences of strain rate on settlement of optical cables

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图 11 不同S_t下归一化后的贯入阻力与位移曲线

Figure 11. Curves of normalized penetration resistance and displacement under different values of S_t

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表 1 不同S_t下两种光缆在硅藻土中预计沉陷量

Table 1 Expected settlements of two kinds of optical cables in diatomite under different conditions of S_t

灵敏度S_t 缆A 缆B

3 0.58D 0.93D

6 0.69D 1.21D

10 0.74D 1.26D

15 0.78D 1.34D

简化公式法（S_t = 1） 0.36D 0.56D

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参考文献(16)

[1]	DAY R W. Engineering properties of diatomaceous fill[J]. Journal of Geotechnical Engineering, 1995, 121(12): 908-910. doi: 10.1061/(ASCE)0733-9410(1995)121:12(908)
[2]	马秋柱, 何智敏, 蔡泽明. 纳米比亚硅藻土的工程特性[J]. 水运工程, 2017, 12: 80-84. https://www.cnki.com.cn/Article/CJFDTOTAL-SYGC201712014.htm MA Zhuqiu, HE Zhimin, CAI Zeming. Engineering properties of diatomite in Namibia[J]. Port & Waterway Engineering, 2017, 12: 80-84. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-SYGC201712014.htm
[3]	任玉宾, 王胤, 杨庆. 典型深海软黏土全流动循环软化特性与微观结构探究[J]. 岩土工程学报, 2019, 41(8): 1562-1568. doi: 10.11779/CJGE201908022 REN Yubin, WANG Yin, YANG Qing. Full-flow cyclic degradation and micro-structure of representative deep-sea soft clay[J]. Chinese Journal of Geotechnical Engineering, 2019, 41(8): 1562-1568. (in Chinese) doi: 10.11779/CJGE201908022
[4]	李铁刚, 熊志方. 海洋硅藻稳定同位素研究进展[J]. 海洋与湖沼, 2010, 41(4): 645-656. https://www.cnki.com.cn/Article/CJFDTOTAL-HYFZ201004028.htm LI Tiegang, XONG Zhifang. Research progress on stable isotopes of Marine diatoms[J]. Oceanologia Et Limnologia Sinica, 2010, 41(4): 645-656. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-HYFZ201004028.htm
[5]	MERIFIELD R S, WHITE D J, RANDOLPH M F. The ultimate undrained resistance of partially-embedded pipelines[J]. Géotechnique, 2008, 58(6): 461-470. doi: 10.1680/geot.2008.58.6.461
[6]	MERIFIELD R S, WHITE D J, RANDOLPH M F. Effect of surface heave on response of partially embedded pipelines on clay[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2009, 135(6): 819-829. doi: 10.1061/(ASCE)GT.1943-5606.0000070
[7]	ZHANG Z, LEUNG C F, CHOW Y K. Pipe–soil interaction on free-span shoulder subject to vortex-induced vibration[J]. Canadian Geotechnical Journal, 2020, 57(11): 1704-1718. doi: 10.1139/cgj-2019-0408
[8]	SENTHILKUMAR, RAJEEV, ROBERT, et al. Undrained load-displacement behavior of partially embedded pipeline on seabed[J]. Journal of Pipeline Systems Engineering and Practice, 2016, 7(1): 4015016.1.
[9]	HU Y, RANDOLPH M F. A practical numerical approach for large deformation problems in soil[J]. International Journal for Numerical and Analytical Methods in Geomechanics, 1998, 22(5): 327-350. doi: 10.1002/(SICI)1096-9853(199805)22:5<327::AID-NAG920>3.0.CO;2-X
[10]	BISCONTIN G, PESTANA J. Influence of peripheral velocity on vane shear strength of an artificial clay[J]. Geotechnical Testing Journal, 2001, 24(4): 423-429. doi: 10.1520/GTJ11140J
[11]	EINAV I, RANDOLPH M. Effect of strain rate on mobilised strength and thickness of curved shear bands[J]. Géotechnique, 2006, 56(7): 501-504. doi: 10.1680/geot.2006.56.7.501
[12]	任玉宾, 杨庆, 王胤, 等. 典型深海软黏土触变特性与微观结构探究[J]. 工程地质学报, 2021, 29(5): 1295-1302. https://www.cnki.com.cn/Article/CJFDTOTAL-GCDZ202105006.htm REN Yubin, YANG Qing, WANG Yin, et al. Experimental study on thixotropic characteristic and microstructural evolution of representative deep-sea soft clay[J]. Journal of Engineering Geology, 2021, 29(5): 1295-1302. (in Chinese) https://www.cnki.com.cn/Article/CJFDTOTAL-GCDZ202105006.htm
[13]	WANG D, WHITE D J, RANDOLPH M F. Large deformation finite element analysis of pipe penetration and large amplitude lateral displacement[J]. Canadian Geotechnical Journal, 2010, 47(8): 842-856.
[14]	WANG D, BIENEN B, NAZEM M, et al. Large deformation finite element analyses in geotechnical engineering[J]. Computers and Geotechnics, 2015, 65: 104-114
[15]	DUTTA S, HAWLADER B, PHILLIPS R. Strain softening and rate effects on soil shear strength in modeling of vertical penetration of offshore pipelines[C]// International Pipeline Conference, Calgary, Alberta, 2012.
[16]	RANDOLPH M F, WHITE D J. Pipeline embedment in deep water: processes and quantitative assessment[C]// Proc Offshore Tech Conf, Houston, 2008.