本文選題：干濕循環(huán) + 約束　； 參考：《貴州大學(xué)》2015年碩士論文

【摘要】：在實際工程中,工程巖體受到約束的情況很多,例如在邊坡支護時,當(dāng)錨桿打入巖體內(nèi)部之后,錨桿周邊的巖體隨即受到約束作用。工程實踐表明這些處理好的邊坡中常有邊坡坍塌等災(zāi)害發(fā)生,說明處理好的邊坡巖石在自然環(huán)境條件下其性質(zhì)在發(fā)生變化,據(jù)此本文以受約束巖體作為研究對象,探究其物理力學(xué)特性在干濕循環(huán)作用下的變化規(guī)律,為巖體工程的設(shè)計、施工和維護安全運行提供理論依據(jù),具有重大的現(xiàn)實意義和理論意義。本文是建立在3個主要試驗的基礎(chǔ)之上,一是受約束的泥質(zhì)白云巖的物理特性實驗,二是干濕循環(huán)作用下受約束的泥質(zhì)白云巖的力學(xué)特性實驗,三是預(yù)應(yīng)力損失觀測試驗。取7組巖樣,在飽水狀態(tài)下進行室內(nèi)干濕循環(huán)試驗,飽水和干燥各12小時為1周期,總共循環(huán)30周期。在循環(huán)過程中,通過觀察記錄巖樣的外觀變化情況,并跟蹤其質(zhì)量和縱波波速等物理特性參數(shù);另外對每增加5個循環(huán)周期進行了單軸壓縮試驗,從而獲得巖樣的單軸抗壓強度、彈性模量、泊松比等力學(xué)特性參數(shù),得出了泥質(zhì)白云巖在干濕循環(huán)作用下物理參數(shù)和力學(xué)參數(shù)的變化規(guī)律。預(yù)應(yīng)力損失觀測試驗是本文的一個主要創(chuàng)新點,這個試驗中模擬了一種對巖體施加約束的方法。在試樣兩端放置兩塊10mm厚的方形鋼板,鋼板通過4根高強度螺桿連接,通過調(diào)節(jié)螺栓的松緊來改變施加應(yīng)力的大小。對這種施加了約束的巖樣進行干濕循環(huán)試驗,在螺桿上貼上應(yīng)變片,采用江蘇東華測試技術(shù)股份有限公司生產(chǎn)的DH3816N靜態(tài)應(yīng)變測試系統(tǒng)采集螺桿的應(yīng)變,由此探究預(yù)應(yīng)力的衰減規(guī)律。試驗結(jié)果表明:泥質(zhì)白云巖在干濕循環(huán)作用下有明顯的損傷劣化現(xiàn)象,巖樣縱波波速、單軸抗壓強度、彈性模量等參數(shù)呈現(xiàn)明顯的下降趨勢。約束巖體的預(yù)應(yīng)力損失呈現(xiàn)比較明顯的規(guī)律性,即循環(huán)周期的初始段和結(jié)束段損失比較明顯,中間段變化比較小,本文對這種規(guī)律性做了初步的分析探討,認為預(yù)應(yīng)力會受到巖體自身性質(zhì)和外部自然環(huán)境雙重因素的影響。
[Abstract]:In practical engineering, the engineering rock mass is subjected to many constraints. For example, when the bolt is inside the rock mass, the rock mass around the anchor rod will be restrained when the slope is supported. Engineering practice shows that slope collapse and other disasters often occur in these treated slopes, indicating that the nature of the treated slope rock is changing under the natural environment. Therefore, the confined rock mass is taken as the research object in this paper. It is of great practical and theoretical significance to explore the variation of its physical and mechanical properties under the action of dry-wet cycle, which provides the theoretical basis for the design, construction and safe operation of rock mass engineering. This paper is based on three main experiments, one is the physical characteristic experiment of the confined muddy dolomite, the other is the mechanical characteristic experiment of the confined muddy dolomite under the action of dry-wet cycle, and the third is the observation test of the prestress loss. Seven groups of rock samples were taken for indoor dry and wet cycle tests under the condition of saturated water. The water saturation and drying were 1 cycle for 12 hours each, and the total cycle was 30 cycles. During the cycle, the appearance changes of rock samples are recorded, and the physical characteristic parameters such as mass and longitudinal wave velocity are tracked, and the uniaxial compression tests are carried out for each additional five cycles. The uniaxial compressive strength, elastic modulus and Poisson's ratio of rock samples are obtained, and the variation of physical and mechanical parameters of muddy dolomite under dry and wet cycles is obtained. The observation test of prestress loss is one of the main innovations in this paper. In this experiment, a method of imposing constraint on rock mass is simulated. Two square steel plates with 10mm thickness were placed at both ends of the specimen. The plates were connected by four high strength screws and the applied stress was changed by adjusting the fastening of bolts. The dry-wet cycle test was carried out on the rock samples with constraints. Strain gauges were attached to the screw, and the strain of the screw was collected by the DH3816N static strain testing system produced by Jiangsu Donghua testing Technology Co., Ltd. Thus, the attenuation law of prestress is explored. The test results show that the muddy dolomite has obvious damage deterioration phenomenon under the action of dry and wet cycle. The longitudinal wave velocity, uniaxial compressive strength and elastic modulus of the rock sample show an obvious downward trend. The prestress loss of confined rock mass shows obvious regularity, that is, the loss of initial and end stages of cycle is obvious, and the change of middle section is relatively small. This paper makes a preliminary analysis and discussion on this regularity. It is considered that the prestress will be affected by both the nature of rock mass and the external natural environment.
【學(xué)位授予單位】：貴州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU452

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本文編號：2017508