本文選題：CDM法　切入點：復合基礎(chǔ)　出處：《大連理工大學》2015年碩士論文

【摘要】：較厚的軟土往往限制了重力式結(jié)構(gòu)在港口工程中的應(yīng)用,傳統(tǒng)地基處理方式在提高地基承載力方面差強人意。水下深層攪拌法(CDM法)以其良好的地基改良特性以及較少的海區(qū)污染,在北歐以及日本等國家被廣泛應(yīng)用于港口工程地基加固。然而在我國,CDM法由于施工工藝及設(shè)備短缺、加固費用昂貴等原因,并未得到廣泛的推廣本文首先根據(jù)中日CDM規(guī)范以及工程設(shè)計經(jīng)驗,歸納CDM的破壞模式,總結(jié)各破壞模式驗算方法。并比較我國《水下深層水泥攪拌法加固軟土地基技術(shù)規(guī)程》、日本《海上工事深層混合處理工法技術(shù)手冊》、日本《港口技術(shù)基準·同解說》設(shè)計計算理論差異。CDM法壁式拌合體地基破壞模式可分為橫向整體破壞與壁間破壞,但我國相關(guān)規(guī)范中缺少對壁式拌合體壁間地基破壞的驗算。因此本文在Prandtl解滑裂線的基礎(chǔ)上,假定滑裂線過渡區(qū)與被動區(qū)的連續(xù)性,推導出復合基礎(chǔ)地基破壞滑裂線形狀。根究該滑裂線形狀,本文采用條分法計算復合基礎(chǔ)地基地基承載力,并通過FLAC 3D驗算其合理性。之后,運用FLAC 3D驗證兩種破壞模式的獨立性。本文根據(jù)該方法并結(jié)合《港口工程地基規(guī)范》提出了壁式拌合體地基承載力驗算的新判據(jù)。塊式拌合體著底形式可分為懸浮式和著底式�，F(xiàn)行規(guī)范中對兩種著底形式的拌合體基底壓力計算假定均為線性分布。根據(jù)本文有限元分析結(jié)果,懸浮和著底式拌合體基底壓力由于下臥土層的塑性變形以及剛度的影響,除趾部小部分的應(yīng)力集中區(qū)域外,最大基底壓力產(chǎn)生于趾部里側(cè)。并且根據(jù)數(shù)值模擬結(jié)果,拌合體內(nèi)剪力最大值產(chǎn)生位置與規(guī)范計算假定相同�，F(xiàn)行中日規(guī)范中壁式拌合體抗壓驗算中,均假定長壁承擔所有上部荷載。根據(jù)本文數(shù)值模擬結(jié)果,由于壁間土的樁側(cè)摩阻力作用以及壁間土對短壁的地基反力的作用,壁間土承擔了一定的豎向荷載。并且長壁最大豎向應(yīng)力并不一定出現(xiàn)在長壁底部。該現(xiàn)象對于懸浮式拌合體尤為如此。此外,本文根據(jù)某實際工程案例,對比分析各種地基處理方案,并且驗算上部結(jié)構(gòu)沿基床內(nèi)部滑裂面抗滑穩(wěn)定性。
[Abstract]:Thick soft soil often limits the application of gravity structures in port engineering. The traditional method of foundation treatment is not satisfactory in improving the bearing capacity of foundation. The underwater deep mixing method and CDM method have good foundation improvement characteristics and less pollution in the sea area. In northern Europe and Japan and other countries are widely used in port engineering foundation reinforcement. However, in China, because of the shortage of construction technology and equipment, the cost of reinforcement is expensive. Firstly, according to the CDM code and engineering design experience of China and Japan, the failure mode of CDM is summarized. This paper summarizes the checking calculation methods of each failure mode, and compares the Technical regulations for strengthening soft soil Foundation by underwater Deep cement mixing method in China, the Technical Manual of Deep mixing treatment method for Offshore works in Japan, and the same solution of Technical Datum of Ports in Japan. Theory difference of Design and calculation. Failure modes of Wall-type mixed Foundation with CDM method can be divided into transverse whole failure and interwall failure. However, there is a lack of checking calculation of the foundation failure between wall and wall in the relevant codes of our country. Therefore, on the basis of Prandtl solution of sliding crack line, the continuity of transition zone and passive zone of sliding crack line is assumed in this paper. In this paper, the bearing capacity of composite foundation is calculated by slice method, and its rationality is verified by FLAC 3D. FLAC 3D is used to verify the independence of the two failure modes. In this paper, a new criterion for checking the bearing capacity of wall mixed foundation is put forward according to this method and combining with the Code of Foundation for Port Engineering. The bottom form of block mixed body can be divided into suspension. In the current code, the calculation of the pressure of two kinds of bottom mixed body is assumed to be linear distribution. According to the results of finite element analysis in this paper, Under the influence of plastic deformation and stiffness of the underlying soil, the maximum base pressure is generated from the inner side of the toe, except for the stress concentration area in a small part of the toe, and according to the results of numerical simulation. The position of the maximum shear force in mixing body is assumed to be the same as that in the code. In the current Chinese and Japanese codes, the wall bearing all the upper loads is assumed to bear all the upper loads. According to the results of numerical simulation in this paper, Because of the effect of pile friction on the soil between the walls and the reaction of the soil between the walls to the foundation of the short wall, The soil between walls bears a certain vertical load, and the maximum vertical stress of the long wall does not necessarily appear at the bottom of the wall. This phenomenon is especially true for suspension mixing. In addition, according to a practical engineering case, All kinds of foundation treatment schemes are compared and analyzed, and the anti-slide stability of superstructure along the sliding surface of the bed is checked.
【學位授予單位】：大連理工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：U655.54

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相關(guān)期刊論文 前1條

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本文編號：1669882