本文選題：長短樁 + 復合地基��； 參考：《華北科技學院》2017年碩士論文

【摘要】：隨著建筑物向高層、深基方向發(fā)展,對于地基抵抗變形的要求越來越高,長短樁復合地基處理技術(shù)也因此在工程實踐中發(fā)展起來。長短樁復合地基能充分發(fā)揮樁體和土體的特性,達到控制沉降、提高安全系數(shù)的目的。但是隨著長短樁復合地基處理方式越來越復雜,其沉降引發(fā)的安全問題越來越突出。因此有必要對長短樁復合地基進行深入的研究。本文首先對長短樁復合地基的沉降變形和承載特性進行研究。然后對長短樁復合地基沉降計算方法進行比較分析。最后通過建立GA-SVM模型對長短樁復合地基進行沉降預測。主要研究內(nèi)容和成果如下:(1)通過室內(nèi)試驗模型的建立,研究樁體的樁長、樁徑、墊層厚度變化對沉降變形的影響,揭示長短樁復合地基的沉降變化規(guī)律。結(jié)果表明:增加長樁長度、短樁長度、樁徑、減小墊層厚度對地基沉降控制有顯著效果。(2)通過對長短樁復合地基的樁身應力、樁土應力比和下臥層應力進行分析,揭示長短樁復合地基的應力特性。結(jié)果表明:樁身應力會出現(xiàn)一個峰值,且該峰值處的樁身應力最大;樁頂?shù)臉锻翍Ρ认仍龃蠛鬁p小,樁端的樁土應力比逐漸增大;下臥層樁身應力相比周圍土體應力較大。(3)結(jié)合工程實例對長短樁復合地基沉降計算方法進行分析,并對其沉降計算值與實測數(shù)據(jù)進行對比研究。結(jié)果表明:等效天然地基計算計算結(jié)果比較符合實際,加權(quán)模量法計算雖然比較簡單,但是沉降計算的誤差比較大。(4)通過GA-SVM預測模型對長短樁復合地基沉降進行預測研究。結(jié)果表明:GA-SVM對長短樁復合地基進行預測擬合程度較好,其沉降預測與現(xiàn)場實測值誤差較小。本文提出的GA-SVM模型對長短樁復合地基沉降預測具有良好的預測精度和適用性,對于巖土工程的安全預測具有良好的指導作用。
[Abstract]:With the development of high building and deep foundation, the requirement of resisting deformation of foundation is more and more high, and the treatment technology of long-long pile composite foundation has been developed in engineering practice. Long and short pile composite foundation can give full play to the characteristics of pile and soil to control settlement and improve safety factor. But as the treatment of long and short pile composite foundation becomes more and more complex, the safety problems caused by its settlement become more and more prominent. Therefore, it is necessary to study the long-long pile composite foundation. In this paper, the settlement, deformation and bearing characteristics of long and short pile composite foundation are studied. Then the settlement calculation method of long and short pile composite foundation is compared and analyzed. Finally, GA-SVM model is established to predict the settlement of long-long pile composite foundation. The main research contents and results are as follows: (1) through the establishment of laboratory test model, the influence of pile length, pile diameter and cushion thickness on settlement deformation is studied, and the rule of settlement variation of long-long pile composite foundation is revealed. The results show that increasing the length of long pile, the length of short pile, the diameter of pile and reducing the thickness of cushion have remarkable effect on the control of foundation settlement. The stress characteristics of long and short pile composite foundation are revealed. The results show that there will be a peak value of pile stress, and the pile body stress at the peak value will be the largest, and the pile-soil stress ratio of the pile top will first increase and then decrease, and the pile-soil stress ratio at the end of the pile will increase gradually. Combined with engineering examples, the settlement calculation method of long-long pile composite foundation is analyzed, and the calculated value of settlement is compared with the measured data. The results show that the calculation results of the equivalent natural foundation are in good agreement with the reality. Although the calculation of weighted modulus method is simple, the error of settlement calculation is relatively large. 4) the settlement of long-long pile composite foundation is forecasted by GA-SVM model. The results show that the weight GA-SVM can predict the composite foundation with long and short piles, and the error between settlement prediction and field measurement is small. The GA-SVM model proposed in this paper has good prediction accuracy and applicability for the settlement prediction of long-long pile composite foundation, and has a good guiding function for the safety prediction of geotechnical engineering.
【學位授予單位】：華北科技學院
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TU753

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本文編號：2016819