地震动力特性对于粉煤灰堆场、填筑体的安全至关重要。根据Seed-Idriss公式计算粉煤灰地基地震应力,通过动三轴试验研究50~200 kPa固结应力和3种不同动应力水平下的特性,得出地震下粉煤灰的动变形、动孔压、破坏形式和动模量弱化等特性。研究结果表明:地震循环应力较大时,破坏形式为双幅动应变达到限值;中等循环应力条件下,固结应力为50 kPa时,破坏形式为累积轴向应变达到限值,固结应力>50 kPa时,破坏形式为双幅动应变达到限值;地震循环应力较小时,粉煤灰不发生变形破坏。相同循环周数下,孔压比随着固结应力的增大而降低;达到变形破坏时,孔压远小于液化值。地震循环应力较大时,在10周循环荷载后,粉煤灰动模量迅速弱化;中等循环应力条件下,循环周数大于临界值后模量弱化指数迅速降低;地震循环应力较小时,粉煤灰的模量弱化不明显。研究成果可为粉煤灰堆场、地基、坝体等的动力计算提供依据。
Abstract
Cyclic properties of fly ash under earthquake load are crucial for the safety of stock yard and filling bodies. In this paper the cyclic deformation, cyclic pore pressure, failure mode and modulus degradation of fly ash under earthquake load were investigated via triaxial test under effective consolidation stress of 50-200 kPa and three different cyclic stress levels. The cyclic shear stress was calculated based on Seed-Idriss's equation. Results revealed that under large cyclic stress level, fly ash failed under the criterion of dual-amplitude axial strain; under medium cyclic stress level and 50 kPa consolidation stress, fly ash failed under the criterion of accumulative axial strain, while when consolidation stress exceeded 50 kPa, fly ash failed under the criterion of dual-amplitude axial strain; under low cyclic stress level, cyclic deformation failure did not occur. At the same cycle, pore pressure ratio decreased with the rising of consolidation stress; pore pressure in fly ash was far below liquefaction criterion when deformation failure occurred. Modulus of fly ash degraded rapidly under large stress level until 10 cycles; under medium cyclic stress level, the modulus degradation index decreased swiftly when cycle number was beyond critical value; degradation of modulus was very small under low cyclic stress level.
关键词
粉煤灰 /
地震 /
动变形 /
破坏形式 /
孔压 /
模量弱化
Key words
fly ash /
earthquake /
cyclic deformation /
failure mode /
pore pressure /
modulus degradation
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参考文献
[1] 高晓云,陈萍. 粉煤灰的基本性质与综合利用现状及发展方向[J]. 能源环境保护, 2012, 26(4): 5-7.
[2] KANIRAJ S R, GAYATHRI V.Permeability and Consolidation Characteristics of Compacted Fly Ash[J]. Journal of Energy Engineering, ASCE, 2004, 130(1): 18-43.
[3] KIM B, PREZZI M, SALGADO R.Geotechnical Properties of Fly and Bottom Ash Mixtures for Use in Highway Embankments[J]. Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 2005, 131(7): 914-924.
[4] 冯海宁,杨有海,龚晓南. 粉煤灰工程特性的试验研究[J]. 岩土力学, 2002, 23(5): 579-582.
[5] 葛折圣,黄晓明,张肖宁,等. 陶粒粉煤灰混凝土在桥涵台背回填中的应用研究[J]. 岩土力学, 2006, 27(11): 2076-2079.
[6] 林彤,刘祖德. 粉煤灰与生石灰加固软土的室内试验研究[J]. 岩土力学, 2003, 24(6): 1049-1052.
[7] 谢海澜,王清. 粉煤灰加固处理吹填泥浆的试验研究[J]. 岩石力学与工程学报, 2005, 24(10): 1811-1816.
[8] ZHUANG X, WANG G, ZHU R.Experimental Study on Unconfined Compressive Strength of Clays Stabilized with Fly Ash and Slag[J]. Chinese Journal of Geotechnical Engineering, 2005, 27(8): 965-969.
[9] 冯美果,陈善雄,余颂,等. 粉煤灰改性膨胀土水稳定性试验研究[J]. 岩土力学, 2007, 28(9): 1889-1893.
[10] 骆亚生,李靖,徐丽. 掺土粉煤灰的工程性质试验研究[J]. 岩土力学, 2009, 30(增2): 67-71.
[11] KANIRAJ S R, HAVANAGI V G.Behavior of Cement-Stabilized Fiber-Reinforced Fly Ash-Soil Mixtures[J]. Journal of Geotechnical and Geoenvironmental Engineering, ASCE, 2001, 127(7): 574-584.
[12] 温明星, 骆亚生,刘紫韦,等. 掺粉煤灰压实黄土环剪试验研究[J]. raybet体育在线
院报, 2016, 33(3): 70-74.
[13] 杨晓松,刘井强,党进谦. 粉煤灰改良氯盐渍土工程特性试验研究[J]. raybet体育在线
院报, 2012, 29(11): 82-86.
[14] 王助贫, 邵龙潭, 孙益振. 基于数字图像测量技术的粉煤灰三轴试样剪切带研究[J]. 岩土工程学报, 2006, 28(9): 45-49.
[15] 梁波,丁立. 粉煤灰作为填料的水稳性试验研究[J]. 岩土工程学报, 2002, 24(1): 112-114.
[16] 明经平,方永凯,孟广训. 粉煤灰湿陷特性的初步研究[J]. 岩土工程学报, 1999, 21(6): 753-756.
[17] 明经平,赵维炳. 粉煤灰湿陷变形的三轴试验和计算[J]. 岩土力学, 2004, 25(增刊): 32-38.
[18] 李时亮,周全能. 粉煤灰作为路堤填料的动力特性试验研究[J]. 岩土力学, 2005, 26(2): 311-314.
[19] 李振,骆亚生,邢义川. 动扭剪荷载作用下粉煤灰动力特性试验研究[J]. 岩石力学与工程学报, 2006, 25(增1): 3080-3086.
[20] 郭莹,张小玲,栾茂田. 初始中主应力系数对中密粉煤灰动模量阻尼比影响的试验研究[J]. 岩土力学, 2008, 29(3): 591-595.
[21] SEED H B, IDRISS I M, ARANGO I.Evaluation of Liquefaction Potential Using Field Performance Data[J]. Journal of the Geotechnical Engineering Division, 1983, 109(3):458-482.
[22] 黄雨, 金晨, 庄之敬, 等. 上海地区第⑤2层砂质粉土的液化特性试验研究[J]. 同济大学学报, 2010, 38(1): 45-49.
[23] 吴波, 孙德安. 非饱和粉土的液化特性研究[J]. 岩土力学, 2013, 34(2): 411-416.
基金
国家自然科学基金项目(51408197,51178165); 河南省科技厅自然科学项目(162102210188); 河南省教育厅自然科学项目(15A560020)
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