發(fā)布時(shí)間：2019-07-05 15:34

【摘要】：在軟土地基上修建低路堤時(shí),軟土地基經(jīng)常會(huì)出現(xiàn)失穩(wěn)、變形過大等問題,從而造成路面開裂,在此情況下通常會(huì)通過修建人工硬殼層對軟基進(jìn)行處治。目前,對于軟土地基人工硬殼層相應(yīng)的設(shè)計(jì)參數(shù)和處治方法并未進(jìn)行深入的研究,且大部分處理方法都是通過工程實(shí)踐和室內(nèi)試驗(yàn)總結(jié)得到的。為優(yōu)化用于處治軟土路基的人工硬殼層設(shè)計(jì)方案,并提出軟土地基上人工硬殼層設(shè)計(jì)參數(shù)的推薦取值范圍,首先利用有限元軟件ABAQUS在基于大、小變形理論基礎(chǔ)上建立軟土地基上路基路面有限元模型,對比分析軟土地基模型對計(jì)算結(jié)果的影響程度,選定能夠合理模擬軟土地基的有限元模型;然后分析人工硬殼層的模量、厚度、寬度等參數(shù)對軟土地基和路面力學(xué)響應(yīng)的影響;最后推薦軟土地基上人工硬殼層設(shè)計(jì)參數(shù)的合理取值范圍。研究結(jié)果表明:含人工硬殼層軟基上修建低路堤后,主要有軟基整體承載力不足導(dǎo)致的剪切破壞、軟基沉降變形過大和路基當(dāng)量模量過低引起的路面提前開裂3種破壞形式;與擴(kuò)展的Drucker-Prager模型相比,基于大變形理論的多孔介質(zhì)彈性模型在模擬軟土地基時(shí)表面沉降增大45.1%,附加應(yīng)力降低4.9%,采用大變形理論模擬軟土地基更合理;硬殼層的模量、厚度和寬度在一定范圍內(nèi)變化時(shí),隨著其數(shù)值的增加,軟土地基的應(yīng)力和位移逐漸降低,路面承受的附加應(yīng)力逐漸增大;推薦軟土地基上人工硬殼層的設(shè)計(jì)模量為150~300 MPa,處治深度為1~2m,每側(cè)寬度比路基邊坡增加1m。
[Abstract]:When the low embankment is built on the soft soil foundation, the soft soil foundation often has the problems of instability and excessive deformation, which leads to the pavement cracking. In this case, the soft foundation will usually be treated by the construction of artificial hard shell. At present, the corresponding design parameters and treatment methods of artificial hard shell on soft soil foundation have not been deeply studied, and most of the treatment methods are summarized through engineering practice and laboratory tests. In order to optimize the design scheme of artificial hard shell used to treat soft soil subgrade, and put forward the recommended value range of artificial hard shell design parameters on soft soil foundation, firstly, the finite element model of subgrade pavement on soft soil foundation is established on the basis of large and small deformation theory by using finite element software ABAQUS, the influence degree of soft soil foundation model on the calculation results is compared and analyzed, and the finite element model which can reasonably simulate soft soil foundation is selected. Then the effects of modulus, thickness and width of artificial hard shell on the mechanical response of soft soil foundation and pavement are analyzed. Finally, the reasonable range of design parameters of artificial hard shell on soft soil foundation is recommended. The results show that after the construction of low embankment on soft foundation with artificial hard shell, there are three kinds of failure forms: shear failure caused by insufficient overall bearing capacity of soft foundation, excessive settlement deformation of soft foundation and early cracking caused by low equivalent modulus of subgrade. Compared with the extended Drucker-Prager model, the elastic model of porous media based on large deformation theory increases the surface settlement by 45.1% and reduces the additional stress by 4.9% when simulating soft soil foundation, so it is more reasonable to use large deformation theory to simulate soft soil foundation. When the modulus, thickness and width of the hard shell change in a certain range, with the increase of its numerical value, the stress and displacement of the soft soil foundation decrease gradually, and the additional stress on the pavement increases gradually. It is recommended that the design modulus of the artificial hard shell on the soft soil foundation is 150 鈮，

本文編號(hào)：2510627