本文選題：多年凍土 + 鉆孔灌注樁��； 參考：《東北林業(yè)大學(xué)》2015年碩士論文

【摘要】：凍土是多相和多成分的復(fù)雜體系,隨著溫度的變化,其固態(tài)冰和液態(tài)水之間相互轉(zhuǎn)化,形成復(fù)雜的物理力學(xué)特性,因此凍土對(duì)溫度的變化非常敏感。在多年凍土進(jìn)行鉆孔灌注樁的施工時(shí),會(huì)隨著樁基礎(chǔ)施工過(guò)程的擾動(dòng)和樁自身的熱量,會(huì)給長(zhǎng)期穩(wěn)定的多年凍土冰層帶來(lái)較大的擾動(dòng)。特別是在澆筑完混凝土之后,由于混凝土水化熱的影響,樁身混凝土的溫度會(huì)逐漸升高,隨著溫度的升高,與樁基礎(chǔ)接觸的多年凍土就會(huì)受到樁身混凝土熱量傳輸?shù)挠绊?溫度也會(huì)隨之提高,隨著熱量的交換,多年凍土的冰凍狀態(tài)會(huì)發(fā)生相應(yīng)的變化,其本身的物理力學(xué)特性也會(huì)發(fā)生相應(yīng)的變化,這樣就會(huì)對(duì)橋梁建設(shè)帶來(lái)嚴(yán)重的影響,極易產(chǎn)生凍脹、融沉等不良地質(zhì)病害。本文依托漠大線(xiàn)林區(qū)伴行公路工程,結(jié)合該工程所在地(大興安嶺島狀多年凍土區(qū))氣溫低、溫差大等氣候條件,研發(fā)一套樁基現(xiàn)場(chǎng)溫度監(jiān)測(cè)系統(tǒng),該系統(tǒng)除了可以克服這些氣候條件,還可以實(shí)時(shí)不間斷的監(jiān)測(cè)現(xiàn)場(chǎng)的溫度,并且可以遠(yuǎn)程的將溫度數(shù)據(jù)傳輸給用戶(hù)端;在K216+746和K205+404兩處工程橋梁所在位置建立鉆孔灌注試樁,結(jié)合本次試驗(yàn)?zāi)軌蛴^測(cè)樁基混凝土灌注后樁-土溫度場(chǎng)的變化趨勢(shì)的目的,給出了試驗(yàn)場(chǎng)溫度監(jiān)測(cè)系統(tǒng)平面布置圖和縱向測(cè)溫特征點(diǎn)布置圖；依據(jù)現(xiàn)場(chǎng)監(jiān)測(cè)的溫度數(shù)據(jù),繪出了兩處試驗(yàn)地樁基內(nèi)部溫度變化曲線(xiàn)圖和樁側(cè)lm、2m處不同深度下的溫度曲線(xiàn)變化圖,從中可以得出樁基混凝土澆筑完后,樁體內(nèi)部溫度場(chǎng)的變化趨勢(shì)、樁側(cè)土體的溫度場(chǎng)變化趨勢(shì)和混凝土水化熱的影響范圍；建立樁基礎(chǔ)溫度場(chǎng)有限元分析模型,利用現(xiàn)場(chǎng)試驗(yàn)的實(shí)測(cè)數(shù)據(jù)驗(yàn)證模型的正確性,并根據(jù)有限元模型,進(jìn)一步分析鉆孔灌注樁與凍土溫度場(chǎng)的分布情況。通過(guò)現(xiàn)場(chǎng)實(shí)測(cè)數(shù)據(jù)分析的結(jié)果和建立在現(xiàn)場(chǎng)實(shí)測(cè)數(shù)據(jù)基礎(chǔ)上的有限元模擬分析的結(jié)果,可以為多年凍土區(qū)樁基施工工藝優(yōu)化和加快施工進(jìn)度提供數(shù)據(jù)支撐。
[Abstract]:Permafrost is a complex system of multiphase and multi-component. With the change of temperature, the solid ice and liquid water transform each other to form complex physical and mechanical properties, so the frozen soil is very sensitive to the change of temperature. In the construction of permafrost bored pile, with the disturbance of pile foundation construction process and the heat of pile itself, it will bring great disturbance to the long-term stable permafrost ice layer. Especially after pouring concrete, the temperature of pile body concrete will increase gradually because of the influence of hydration heat of concrete. With the increase of temperature, the permafrost in contact with pile foundation will be affected by the heat transfer of pile body concrete. With the exchange of heat, the frozen state of permafrost will change correspondingly, and the physical and mechanical properties of permafrost will also change accordingly, which will have a serious impact on the bridge construction. It is easy to produce frost heaving, thawing and other bad geological diseases. In this paper, based on the auxiliary highway project in Moda-line forest area and the climate conditions such as low temperature and large temperature difference in the site of the project (the island permafrost region of Daxing'anling), a set of in-situ temperature monitoring system for pile foundation is developed. In addition to overcoming these climatic conditions, the system can monitor the temperature of the site in real time and continuously, and can remotely transmit the temperature data to the user, and establish the bored cast-in-place test pile at the location of two engineering bridges, K216,746 and K205,404. Combined with the purpose of observing the change trend of the pile-soil temperature field after the pile foundation concrete pouring in this experiment, the plane layout map and the longitudinal temperature characteristic point layout map of the temperature monitoring system of the test site are given, and the temperature data of the field monitoring are given. The curves of temperature change inside the pile foundation in two test plots and the temperature curves at different depths at lmm 2 m on the side of the pile are drawn, from which the variation trend of the temperature field inside the pile body after pouring the pile foundation concrete can be obtained. The variation trend of soil temperature field and the influence range of concrete hydration heat on the pile side are analyzed, the finite element analysis model of the temperature field of pile foundation is established, and the correctness of the model is verified by the measured data of field test, and according to the finite element model, The distribution of temperature field between bored pile and frozen soil is further analyzed. Through the analysis of the field measured data and the results of finite element simulation based on the field measured data, the data support can be provided for optimizing the construction technology of pile foundation in permafrost region and speeding up the construction progress.
【學(xué)位授予單位】：東北林業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：U443.15

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