本文關(guān)鍵詞：基于不同初始靜偏應(yīng)力的結(jié)構(gòu)性軟黏土動(dòng)力特性試驗(yàn)研究　出處：《公路交通科技》2017年10期 　論文類型：期刊論文

  更多相關(guān)文章： 道路工程 動(dòng)力特性 GCTS動(dòng)靜扭剪儀 結(jié)構(gòu)性軟黏土 屈服應(yīng)變

【摘要】：以天津?yàn)I海新區(qū)結(jié)構(gòu)性海積軟土為研究對象,采用GCTS動(dòng)靜扭剪試驗(yàn)儀,基于正弦波與方波兩種波形,在固結(jié)排水條件下施加不同初始靜偏應(yīng)力,通過考慮循環(huán)振次、應(yīng)力幅值、振動(dòng)頻率以及圍壓等因素對土體結(jié)構(gòu)的影響,研究結(jié)構(gòu)性軟黏土的動(dòng)力特性。試驗(yàn)結(jié)果表明:初始靜偏應(yīng)力小于土體初始屈服應(yīng)力時(shí),施加靜偏應(yīng)力增加了土體固結(jié)度,提高了其結(jié)構(gòu)強(qiáng)度,應(yīng)變軟化現(xiàn)象減弱,累積塑性應(yīng)變曲線中屈服點(diǎn)對應(yīng)的應(yīng)力值大。初始靜偏應(yīng)力大于土體初始屈服應(yīng)力時(shí),土體初始結(jié)構(gòu)破壞,出現(xiàn)嚴(yán)重的應(yīng)變軟化現(xiàn)象,累積塑性應(yīng)變曲線迅速由穩(wěn)定型轉(zhuǎn)變?yōu)榕R界型,且在同條件下,方波應(yīng)變值始終大于正弦波�？讐鹤兓c初始靜偏應(yīng)力有關(guān),隨著靜偏應(yīng)力增大其孔壓滯后現(xiàn)象嚴(yán)重。土體屈服應(yīng)變隨初始靜偏應(yīng)力增大而增加,靜偏應(yīng)力及振次相同時(shí),方波作用下的土體屈服應(yīng)變值小于正弦波。兩種波形下,土體屈服應(yīng)變隨振次增加均呈減小趨勢,且最終均會(huì)趨于一點(diǎn),正弦波趨于相同數(shù)值下的振次遠(yuǎn)大于方波。土體動(dòng)強(qiáng)度隨應(yīng)變標(biāo)準(zhǔn)提高而呈現(xiàn)增大趨勢,應(yīng)變標(biāo)準(zhǔn)為屈服應(yīng)變值時(shí),動(dòng)強(qiáng)度曲線表現(xiàn)為先陡后緩,其他應(yīng)變標(biāo)準(zhǔn)下動(dòng)強(qiáng)度曲線較為平緩。兩種波形下的動(dòng)強(qiáng)度隨振次增加而減小,最終均會(huì)趨于一點(diǎn),且正弦波值大于方波。
[Abstract]:Taking the structural marine soft soil in Tianjin Binhai New area as the research object, using GCTS static and torsional shear test instrument, based on sinusoidal wave and square wave, different initial static deflection stress is applied under the condition of consolidation and drainage. The effects of cyclic vibration times, stress amplitude, vibration frequency and confining pressure on soil structure are considered. The dynamic characteristics of structural soft clay are studied. The experimental results show that when the initial static deflection stress is smaller than the initial yield stress, the application of static deflection stress increases the consolidation degree of the soil and improves its structural strength. The strain softening phenomenon is weakened and the stress corresponding to the yield point in the cumulative plastic strain curve is large. When the initial static deflection stress is larger than the initial yield stress of the soil the initial structure of the soil is destroyed and serious strain softening occurs. The cumulative plastic strain curve changes rapidly from stable type to critical type, and under the same conditions, the square wave strain value is always larger than sine wave. The change of pore pressure is related to the initial static stress. With the increase of static stress, the pore pressure lag phenomenon is serious, and the yield strain of soil increases with the increase of initial static stress, when the static stress and vibration times are the same. The yield strain of soil under square wave is smaller than that of sinusoidal wave. Under the two waveforms, the yield strain of soil decreases with the increase of vibration frequency, and will tend to a point in the end. The dynamic strength of soil increases with the increase of strain standard, when the strain standard is yield strain, the dynamic strength curve is steep first and then slow. The dynamic intensity curves under other strain standards are relatively gentle. The dynamic strength of the two waveforms decreases with the increase of vibration frequency, and eventually tends to a point, and the sine wave value is larger than the square wave.
【作者單位】： 天津城建大學(xué)天津市軟土特性與工程環(huán)境重點(diǎn)實(shí)驗(yàn)室;天津港中煤華能煤碼頭有限公司;
【基金】：國家自然科學(xué)基金項(xiàng)目(41372291) 天津市科技計(jì)劃項(xiàng)目(15JCZDJC40600,15ZCZDSF00220)
【分類號】：U414
【正文快照】： strain value is always larger than the sine wave strain value under the same condition;(3)the pore pressurechange is associated with initial static deviatoric stress,the pore pressure lagging phenomenon is serious withthe increase of static deviatoric st

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