長(zhǎng)期反復(fù)荷載作用下軟黏土地基的變形特性

師旭超 孫運(yùn)德 士賀飛

摘 要： 軟黏土地基在長(zhǎng)期反復(fù)荷載作用下容易產(chǎn)生變形大、沉降時(shí)間長(zhǎng)且難于預(yù)測(cè)等問(wèn)題。針對(duì)該問(wèn)題，通過(guò)太沙基一維固結(jié)理論，求解了矩形及梯形反復(fù)荷載作用下軟黏土地基的一維固結(jié)解析解;利用ABAQUS有限元軟件，提出了一種反復(fù)荷載作用下軟黏土地基長(zhǎng)期固結(jié)變形的數(shù)值分析預(yù)測(cè)方法。利用該方法結(jié)合工程實(shí)例詳細(xì)分析了反復(fù)荷載下軟黏土地基沉降、孔隙壓力和有效應(yīng)力及孔隙比等隨時(shí)間的長(zhǎng)期發(fā)展變化規(guī)律，發(fā)現(xiàn)沉降量與反復(fù)荷載的水平加載段時(shí)間成正比;孔隙水壓力的最終發(fā)展趨勢(shì)是圍繞0值上下波動(dòng);有效應(yīng)力隨著加載次數(shù)逐漸增加;孔隙比的變化與土層深度、加載大小與加載次數(shù)有關(guān)，并將不同荷載類型下的模擬值、理論值和實(shí)測(cè)數(shù)據(jù)進(jìn)行了分析比對(duì)，發(fā)現(xiàn)等效的反復(fù)荷載下的沉降曲線與實(shí)測(cè)值吻合較好。

關(guān)鍵詞： 地基;固結(jié)方程;反復(fù)荷載;固結(jié)變形;數(shù)值模擬

中圖分類號(hào)：TU447? ? 文獻(xiàn)標(biāo)志碼：A? ?文章編號(hào)：2096-6717（2020）02-0023-07

Deformation characteristics of soft soil foundation under long-term repeated loading

Shi Xuchao， Sun Yunde， Shi Hefei

（College of Civil Engineering and Architecture， Henan University of Technology， Zhengzhou 450001， P.R.China）

Abstract：? Soft soil foundations are prone to large deformation， long settling time and difficult to predict under long-term repeated loading.Aiming at this problem， the one-dimensional consolidation analytical solution of soft soil foundation under rectangular and trapezoidal repeated loads is solved by the one-dimensional consolidation theory of K.Terzaghi.The soft soil under repeated loading is proposed by ABAQUS finite element software.Numerical analysis and prediction method for long-term consolidation deformation of foundation.This method is combined with engineering examples to analyze the long-term development and change of soft soil foundation settlement， pore pressure， effective stress and void ratio under repeated loading with time.It is found that the settlement is proportional to the horizontal loading time of repeated load; pore water the final development trend of pressure is to fluctuate around 0; the effective stress increases with the total number of loading times; the change of void ratio is related to soil depth， loading size and loading times， the simulated values， theoretical values and measured data under different load types are compared and analyzed， and the settlement curve under the equivalent repeated load was found to be in good agreement with the actual measurement.

Keywords： foundation; consolidation equation; repeated load; consolidation deformation; numerical simulation

隨著經(jīng)濟(jì)的不斷發(fā)展，在軟黏土地基上的工程建設(shè)越來(lái)越多，如油罐、筒倉(cāng)、港口集裝箱堆場(chǎng)等。地基在運(yùn)營(yíng)期間承受長(zhǎng)期反復(fù)荷載作用，由于荷載情況復(fù)雜多變，載荷波動(dòng)較大，地基經(jīng)常會(huì)出現(xiàn)變形大、沉降時(shí)間長(zhǎng)且難于預(yù)測(cè)等問(wèn)題。許多學(xué)者根據(jù)其實(shí)際變化規(guī)律進(jìn)行統(tǒng)計(jì)分析，將實(shí)際荷載進(jìn)行數(shù)學(xué)化，等效為有規(guī)律的加載類型，Rahal等[1]通過(guò)將筒倉(cāng)荷載等效為正弦波載，對(duì)意大利的……