本文關鍵詞：基于不同初始靜偏應力的結構性軟黏土動力特性試驗研究　出處：《公路交通科技》2017年10期 　論文類型：期刊論文

  更多相關文章： 道路工程 動力特性 GCTS動靜扭剪儀 結構性軟黏土 屈服應變

【摘要】：以天津濱海新區(qū)結構性海積軟土為研究對象,采用GCTS動靜扭剪試驗儀,基于正弦波與方波兩種波形,在固結排水條件下施加不同初始靜偏應力,通過考慮循環(huán)振次、應力幅值、振動頻率以及圍壓等因素對土體結構的影響,研究結構性軟黏土的動力特性。試驗結果表明:初始靜偏應力小于土體初始屈服應力時,施加靜偏應力增加了土體固結度,提高了其結構強度,應變軟化現象減弱,累積塑性應變曲線中屈服點對應的應力值大。初始靜偏應力大于土體初始屈服應力時,土體初始結構破壞,出現嚴重的應變軟化現象,累積塑性應變曲線迅速由穩(wěn)定型轉變?yōu)榕R界型,且在同條件下,方波應變值始終大于正弦波。孔壓變化與初始靜偏應力有關,隨著靜偏應力增大其孔壓滯后現象嚴重。土體屈服應變隨初始靜偏應力增大而增加,靜偏應力及振次相同時,方波作用下的土體屈服應變值小于正弦波。兩種波形下,土體屈服應變隨振次增加均呈減小趨勢,且最終均會趨于一點,正弦波趨于相同數值下的振次遠大于方波。土體動強度隨應變標準提高而呈現增大趨勢,應變標準為屈服應變值時,動強度曲線表現為先陡后緩,其他應變標準下動強度曲線較為平緩。兩種波形下的動強度隨振次增加而減小,最終均會趨于一點,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】： 天津城建大學天津市軟土特性與工程環(huán)境重點實驗室;天津港中煤華能煤碼頭有限公司;
【基金】：國家自然科學基金項目(41372291) 天津市科技計劃項目(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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