發(fā)布時(shí)間：2018-06-21 11:43

  本文選題：深基坑 + 蠕變��； 參考：《武漢輕工大學(xué)》2013年碩士論文

【摘要】：隨著我國改革開放的不斷深入，我國的經(jīng)濟(jì)建設(shè)迅猛發(fā)展，城市建設(shè)中高層、超高層的建筑日益增多，這使得巖土深基坑支護(hù)成了熱門�；庸こ痰闹ёo(hù)結(jié)構(gòu)、開挖方案和土的蠕變特性都將會(huì)對基坑變形控制造成影響，從而進(jìn)一步影響到基坑的安全性。本文分析了目前基坑設(shè)計(jì)中常用的彈性抗力法計(jì)算過程。該方法以彈性理論為基礎(chǔ)，在土壓力計(jì)算中，關(guān)鍵參數(shù)m值的確定依賴于工程與個(gè)人經(jīng)驗(yàn)，參數(shù)的取值無法考慮基坑軟土的蠕變特性，可能存在較大誤差。因此，，對于含有流變特性地層的基坑支護(hù)工程，需要使用有限元方法驗(yàn)證設(shè)計(jì)方案。 本文研究了巖土工程中常見的本構(gòu)模型與蠕變模型后，以武漢某深基坑工程為例，對使用傳統(tǒng)設(shè)計(jì)方法設(shè)計(jì)的基坑支護(hù)方案，采用有限元計(jì)算軟件ABAQUS來模擬驗(yàn)算。在模擬開挖過程時(shí)，引入考慮了軟土塑性與蠕變相耦合的Drucker－Prager模型來模擬場地內(nèi)淤泥質(zhì)粉質(zhì)粘土。該計(jì)算模型考慮了軟土的蠕變特性，分析計(jì)算結(jié)果后得到了基坑側(cè)壁變形的蠕變規(guī)律。 通過分析基坑開挖過程中的變形監(jiān)測數(shù)據(jù)，得出了SMW工法樁在實(shí)際工程中的變形特點(diǎn)。再將有限元法的模型計(jì)算結(jié)果與實(shí)際監(jiān)測結(jié)果對比，結(jié)果顯示變形數(shù)據(jù)基本吻合，從而驗(yàn)證了基坑有限元計(jì)算模型的假設(shè)與計(jì)算的合理性。最后，根據(jù)基坑變形蠕變特點(diǎn)，改進(jìn)了的基坑支護(hù)的方式，將改進(jìn)支護(hù)方案有限元模型計(jì)算結(jié)果與原方案的結(jié)果對比，得到了基坑周圍土體與支護(hù)結(jié)構(gòu)的應(yīng)力與變形變化情況。計(jì)算表明軟土的總變形量中蠕變變形量大于53.6%。由此可見減小基坑軟土層的蠕變對基坑的安全有著顯著的意義。對比結(jié)果再次證明了軟土的蠕變將對基坑變形產(chǎn)生重要影響。因此，研究軟土的蠕變特性，在基坑支護(hù)設(shè)計(jì)中考慮巖土的蠕變特性具有重要的理論價(jià)值和實(shí)踐意義。
[Abstract]:With the deepening of China's reform and opening up, the rapid development of China's economic construction, urban construction in the high-rise, high-rise buildings are increasing, which makes the rock and soil deep foundation pit support has become a hot. The supporting structure of foundation pit, excavation scheme and creep characteristics of soil will affect the deformation control of foundation pit, which will further affect the safety of foundation pit. In this paper, the calculation process of elastic resistance method commonly used in foundation pit design is analyzed. This method is based on the elastic theory. In the calculation of earth pressure, the determination of the key parameter m depends on engineering and personal experience, and the parameter value can not consider the creep characteristics of soft soil of foundation pit, and there may be great errors. Therefore, the finite element method should be used to verify the design scheme for foundation pit support engineering with rheological characteristics. After studying the common constitutive and creep models in geotechnical engineering, taking a deep foundation pit project in Wuhan as an example, the finite element calculation software Abaqus is used to simulate the checking calculation of the foundation pit support scheme designed by the traditional design method. A Drucker-Prager model was introduced to simulate silty clay in the site considering the coupling of plasticity and creep of soft soil. The creep behavior of soft soil is considered in this model, and the creep law of lateral wall deformation of foundation pit is obtained by analyzing the calculated results. Based on the analysis of deformation monitoring data during excavation of foundation pit, the deformation characteristics of SMW pile in practical engineering are obtained. The results of finite element method are compared with the results of actual monitoring. The results show that the deformation data are in good agreement with each other, which verifies the hypothesis and rationality of the finite element calculation model of foundation pit. Finally, according to the characteristics of deformation and creep of foundation pit, the improved method of foundation pit support is improved. The results of finite element model calculation of improved support scheme are compared with those of the original scheme, and the stress and deformation changes of soil and supporting structure around the foundation pit are obtained. The results show that the creep deformation of soft soil is greater than 53.6. It can be seen that reducing the creep of soft soil is of great significance to the safety of foundation pit. The results show that the creep of soft soil will have an important effect on foundation pit deformation. Therefore, it is of great theoretical value and practical significance to study the creep characteristics of soft soil and to consider the creep characteristics of rock and soil in the design of foundation pit support.
【學(xué)位授予單位】：武漢輕工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2013
【分類號】：TU473.2

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