陕西延安Q<sub>2</sub>原状黄土抗拉强度试验研究

孙纬宇; 梁庆国; 严松宏; 欧尔峰; 邵森林

陕西延安Q₂原状黄土抗拉强度试验研究

孙纬宇^{1, 2,},
梁庆国^{1, 2},
严松宏^{1, 2},
欧尔峰^{1, 2},
邵森林^{1, 2}

1.
兰州交通大学甘肃省道路桥梁与地下工程重点实验室, 兰州 730070
2.
兰州交通大学土木工程学院, 兰州 730070

基金项目:

国家自然科学基金项目“黄土抗拉强度和各向异性研究” 41262010

长江学者和创新团队发展计划项目 IRT1139

兰州交通大学“青蓝”人才工程项目 QL-08-19A

甘肃省基础研究创新群体资助项目 145RJIA332

详细信息

作者简介:
孙纬宇(1988-), 男, 硕士研究生, 主要从事黄土隧道工程研究。E-mail:448221362@qq.com

中图分类号: TU432
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- 被引次数: 0
出版历程
- 收稿日期: 2015-01-22
- 刊出日期: 2015-09-28

EXPERIMENTAL STUDY ON TENSILE STRENGTH OF UNDISTUBED Q₂ LOESS FROM YANAN SHANNXI, CHINA

SUN Wei-yu^{1, 2
,},
Liang Qing-guo^{1, 2},
YAN Song-hong^{1, 2},
OU Er⁃feng^{1, 2},
SHAO Sen-lin^{1, 2}

1.
Key Laboratory of Road & Bridge and Underground Engineering of Gansu Province, Lanzhou 730070, China
2.
School of Civil Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China

摘要

摘要: 对陕西延安新宝塔山隧道Q₂原状黄土进行了不同加载速率的无侧限抗压与贯入抗拉试验, 研究了Q₂原状黄土抗压与抗拉强度的影响因素。结果表明:加载速率对宝塔山Q₂原状黄土抗压和抗拉强度影响较大, 抗压强度与抗拉强度随加载速率增大而增大; 高径比对抗拉强度也有较大影响, 试验时当高径比控制在1.0左右时, 高径比对宝塔山Q₂原状黄土的抗拉强度影响相对较小, 因此采用轴向压裂法测量黄土的抗拉强度时, 高径比宜控制在1.0;在试验加载速率范围内, 加载速率对宝塔山Q₂原状黄土的压拉比影响不大, 其压拉比在9.88~13.68范围内变化。
- Q₂原状黄土 /
- 抗拉强度 /
- 加载速率 /
- 压拉强度比
Abstract: The unconfined compressive and penetration tensile tests were conducted with different loading rates on undisturbed Q₂ loess from Baotashan Tunnel in Yan'an, Shanxi, and the impacts on the unconfined compressive strength and tensile strength were studied. It shows that the loading rates have a great impact on the compressive strength and tensile strength, which all increase with the increase of loading speed. The ratios of height to diameter have a great influence on the tensile strength of the Q₂ loess, when the ratio of height to diameter of the samples is about 1.0, the impact on the tensile strength tends to be relatively small. Therefore, when the tensile strength of loess is to be measured by axial unconfined penetration test, the ratio of height to diameter of the samples should be 1.0. Within the scope of the test loading rates, the loading rates have little effect on the ratios of compressive strength to tensile ratio for the undisturbed Q₂ loess in Baotashan tunnel, which vary between 9.88 and 13.68.
- undisturbed Q₂ loess /
- tensile strength /
- loading rate /
- ratio of compressive strength to tensile strength

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图 1 抗拉强度测定模型

Figure 1. Model of tensile strength measurement

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图 2 试验装置

Figure 2. The test apparatus

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图 3 拉应力-贯入深度曲线

Figure 3. Curves of tensile stress vs. penetration depth of loess samples

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图 4 抗压/抗拉强度与加载速度关系

Figure 4. Relation curve of compressive and tensile strength with loading rates

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图 5 抗压与抗拉破坏形态

Figure 5. The unconfined compressive and tensile failure pattern

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图 6 不同高径比试验前与试验后试样

Figure 6. Samples before and after test with different height-diameter ratios

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图 7 不同高径比下拉应力与贯入深度关系

Figure 7. Relationship of stress and penetration depth at different height-diameter ratio

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图 8 高径比与抗拉强度关系曲线

Figure 8. Relationship of tensile strength and height-diameter ratio

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图 9 不同高径比抗拉强度降低幅度值

Figure 9. Reduction of the tensile strength at different height-diameter ratios

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图 10 1.25 mm/min时抗压与抗拉强度关系

Figure 10. Correlation of unconfined compressive strength with tensile strength at 1.25 mm/min

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图 11 压拉比与加载速率的关系

Figure 11. Relation between ratio of compressive strength to tensile strength ration and loading rates

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表 1 试验用Q₂黄土的物性指标

Table 1. Physical parameters of Q₂ loess

w/%	ρ/(g·cm^-3)	d_s	w_L/%	w_p/%	e	α_v/MPa^-1
19.64	2.01	2.638	29.2	13.25	0.597	0.09
注：w—含水量；ρ—湿密度；d_s—比重；w_L—液限；w_p—塑限；e—孔隙比；α_v—压缩系数

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