發(fā)布時間：2018-05-10 05:14

  本文選題：承壓水頭變化 + 基坑　； 參考：《巖土工程學報》2017年02期

【摘要】：根據(jù)深大基坑坑底弱透水層的一維越流模型,求解了承壓水頭變化引起的坑底弱透水層中的超靜孔隙水壓力和出逸比降的解析表達式。當坑底土層滲透系數(shù)較大時,出逸比降計算結果與傳統(tǒng)方法的出逸比降求解結果一致,驗證了出逸比降解析解的正確性�；诔鲆荼冉到馕鼋�,分析了動態(tài)承壓水作用下坑底出逸比降的變化規(guī)律和影響因素。結果表明:當基坑坑底弱透水層厚度一定時,土體滲透系數(shù)、壓縮模量或承壓水頭波動周期越大,出逸比降波動越明顯,幅值越大,相位差越小;出逸比降影響因素可通過與土體滲透系數(shù)和壓縮模量正相關,與承壓水頭波動的角頻率和弱透水層厚度的平方負相關的無量綱因子統(tǒng)一表示。最后通過工程實例表明,對于坑底弱透水層滲透系數(shù)較小的情況,降承壓水頭引起的出逸比降減小幅度不大并存在明顯滯后性,對基坑的抗?jié)B流穩(wěn)定性具有不利影響。
[Abstract]:Based on the one-dimensional overflowing model of weak permeable layer at the bottom of deep and large foundation pit, the analytical expressions of excess pore water pressure and escape ratio drop caused by the change of confined water head in weak permeable layer of deep foundation pit are obtained. When the permeability coefficient of the bottom layer is large, the calculated results of the escape ratio drop are consistent with those of the traditional method, which verifies the correctness of the analytical solution of the escape ratio drop. Based on the analytical solution of escape ratio drop, the variation law and influencing factors of escape ratio drop under dynamic pressure water are analyzed. The results show that when the thickness of weak permeable layer at the bottom of the pit is constant, the larger the fluctuation period of soil permeability coefficient, compression modulus or confined water head is, the more obvious the fluctuation of escape ratio is, the larger the amplitude is, and the smaller the phase difference is. The influencing factors of escape ratio drop can be expressed by the dimensionless factor, which is positively correlated with the soil permeability coefficient and compression modulus, and negatively correlated with the angular frequency of the pressure head fluctuation and the square of the thickness of the weak permeable layer. Finally, the engineering example shows that for the case where the permeability coefficient of the weak permeable layer at the bottom of the pit is small, the drop of escape ratio caused by the water head under the pressure drop is not large and there is obvious hysteresis, which has a negative effect on the stability of seepage resistance of foundation pit.
【作者單位】： 浙江大學濱海和城市巖土工程研究中心;浙江大學軟弱土與環(huán)境土工教育部重點實驗室;
【基金】：國家自然科學基金項目(51278462,51278453,51678523);國家自然科學基金重點項目(51338009) 教育部高校博士點專項科研基金項目(20120101110029)
【分類號】：TU753

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本文編號：1867926