本文選題：后張法預(yù)應(yīng)力結(jié)構(gòu) + 灌漿泌水��； 參考：《北京交通大學(xué)》2015年博士論文

【摘要】：在土建行業(yè)后張結(jié)構(gòu)體系中,漿體是保證預(yù)應(yīng)力筋免遭腐蝕的最后一道防線。預(yù)應(yīng)力孔道的灌漿作用在于對(duì)預(yù)應(yīng)力筋進(jìn)行防腐保護(hù),并提供預(yù)應(yīng)力筋與孔道周?chē)炷林g的粘結(jié)力。這些目標(biāo)實(shí)現(xiàn)的前提是預(yù)應(yīng)力孔道完全被漿體所灌滿,但漿體泌水的存在使孔道灌漿完全密實(shí)變得十分困難,孔道灌漿不密實(shí)而導(dǎo)致預(yù)應(yīng)力體系的腐蝕是后張?bào)w系中一直存在的問(wèn)題。本文提出了兩項(xiàng)防治灌漿泌水的措施,重點(diǎn)研究了以無(wú)泌水的瀝青基材料替代水泥基材料進(jìn)行灌漿的技術(shù),通過(guò)對(duì)其材料配合比、可灌性、對(duì)預(yù)應(yīng)力損失的影響規(guī)律以及與預(yù)應(yīng)力筋的粘結(jié)性能等方面的研究,實(shí)現(xiàn)了瀝青基灌漿技術(shù)在后張預(yù)應(yīng)力結(jié)構(gòu)中的應(yīng)用。本文的主要研究?jī)?nèi)容和成果概括如下：(1)現(xiàn)有灌漿工藝和材料的灌漿試驗(yàn)結(jié)果表明,預(yù)應(yīng)力孔道內(nèi)都會(huì)出現(xiàn)灌漿不密實(shí)的現(xiàn)象。探討了水泥漿體泌水的過(guò)程和減小泌水的措施,以改進(jìn)預(yù)應(yīng)力孔道結(jié)構(gòu)層次為出發(fā)點(diǎn),開(kāi)發(fā)出一種組合橡膠棒以成型帶埡口預(yù)應(yīng)力孔道,研究了其解決漿體泌水危害的機(jī)理。以高速鐵路32m簡(jiǎn)支箱梁為原型,設(shè)計(jì)并進(jìn)行了足尺預(yù)應(yīng)力孔道灌漿密實(shí)性對(duì)比試驗(yàn)。結(jié)合試驗(yàn),深入分析了漿體泌水在孔道中產(chǎn)生、傳輸和分布的特性,研究了孔道彎起高度對(duì)灌漿密實(shí)率的影響規(guī)律。試驗(yàn)結(jié)果表明,使用帶埡口孔道能夠使?jié){體泌水形成的空洞與預(yù)應(yīng)力筋相分離,避免預(yù)應(yīng)力筋遭受腐蝕,對(duì)于后張結(jié)構(gòu)中的平直和具有一定彎起角度的預(yù)應(yīng)力孔道,帶埡口孔道的灌漿密實(shí)性遠(yuǎn)優(yōu)于圓形孔道。(2)確定了瀝青基灌漿材料的設(shè)計(jì)目標(biāo)和試驗(yàn)方案。經(jīng)過(guò)初步試驗(yàn),確定了巖瀝青為基質(zhì)瀝青的改性瀝青,其摻加比例為12.5%。在此基礎(chǔ)上,通過(guò)對(duì)不同配合比瀝青基灌漿材料的粘度試驗(yàn)、粘溫變化規(guī)律研究及抗剪強(qiáng)度試驗(yàn),得到瀝青基灌漿材料的配合比為：基質(zhì)瀝青+巖瀝青(12.5%)+(消石灰：水泥=1：9)(40%),該配合比下瀝青基灌漿材料的常溫抗剪強(qiáng)度為697.21 kPa,其可灌溫度應(yīng)高于115℃。以增加消石灰摻量和添加纖維為途徑,得到改進(jìn)型瀝青基灌漿材料配合比為：基質(zhì)瀝青+巖瀝青(12.5%)+(消石灰：水泥=3：7)(40%)+纖維(1%),該改進(jìn)型瀝青基灌漿材料的抗剪強(qiáng)度約為普通型的2倍,其可灌溫度應(yīng)高于140℃。(3)推導(dǎo)了瀝青基材料在孔道中的對(duì)流換熱系數(shù)理論計(jì)算公式,建立了灌漿試驗(yàn)梁有限元模型,通過(guò)對(duì)灌漿過(guò)程的模擬計(jì)算,確定了灌漿工藝關(guān)鍵參數(shù)為：合適的灌漿流量為50 L/min;合理的灌漿溫度為：入口溫度為160℃、壁面溫度為60℃；合適的灌漿壓力為0.8 MPa。通過(guò)對(duì)試驗(yàn)梁及外掛預(yù)應(yīng)力孔道的現(xiàn)場(chǎng)灌漿試驗(yàn),驗(yàn)證了瀝青基灌漿材料的灌漿工藝參數(shù)的正確性和灌漿效果的有效性。(4)通過(guò)對(duì)采用瀝青基材料灌漿的混凝土梁溫度場(chǎng)及應(yīng)力場(chǎng)的計(jì)算可得,預(yù)應(yīng)力孔道的成孔材料應(yīng)選擇HDPE材質(zhì),灌漿時(shí)間是影響溫度場(chǎng)和應(yīng)力場(chǎng)的最主要參數(shù),文中給出的各漿體溫度下,混凝土的最大拉、壓應(yīng)力均小于規(guī)范規(guī)定值。與混凝土梁溫度場(chǎng)和應(yīng)力場(chǎng)的實(shí)測(cè)數(shù)據(jù)對(duì)比可得,本文計(jì)算值與溫度場(chǎng)實(shí)測(cè)值的誤差小于10%,與應(yīng)力場(chǎng)實(shí)測(cè)值的誤差小于15%,表明本文的計(jì)算結(jié)果準(zhǔn)確有效。建立了瀝青基材料灌漿適用性方程,可得出不同強(qiáng)度等級(jí)混凝土在不同漿體溫度下的安全灌漿時(shí)間,從而為采用瀝青基材料的后張結(jié)構(gòu)灌漿施工提供依據(jù)。(5)通過(guò)試驗(yàn)可得,漿體溫度下預(yù)應(yīng)力鋼絞線各項(xiàng)力學(xué)性能均可達(dá)到原指標(biāo)值的0.9倍,應(yīng)力松弛最大可達(dá)6.36%。漿體溫度作用后,其力學(xué)性能指標(biāo)可恢復(fù)到原指標(biāo)值的0.965倍以上,應(yīng)力松弛最大為1.71%。根據(jù)試驗(yàn)結(jié)果,得到了漿體溫度作用下及作用后的預(yù)應(yīng)力鋼絞線力學(xué)性能退化模型和應(yīng)力松弛計(jì)算模型。建立了由漿體溫度引起的短期和長(zhǎng)期預(yù)應(yīng)力損失模型,與現(xiàn)場(chǎng)預(yù)應(yīng)力實(shí)測(cè)結(jié)果對(duì)比,最大誤差為14.1%,驗(yàn)證了該模型的準(zhǔn)確性。通過(guò)計(jì)算可得,瀝青基材料灌漿最不利工況下產(chǎn)生的長(zhǎng)期預(yù)應(yīng)力損失率為2.73%。(6)在瀝青基灌漿材料粘彈性本構(gòu)關(guān)系基礎(chǔ)上,推導(dǎo)出預(yù)應(yīng)力筋-瀝青基材料粘結(jié)受力理論解,得到了鋼絞線、鋼絞線-基體界面以及瀝青基材料基體等的應(yīng)力分布特征。探討了施加荷載、預(yù)應(yīng)力筋與基體的半徑比、瀝青基材料溫度以及荷載施加時(shí)間等因素對(duì)預(yù)應(yīng)力筋-瀝青基材料之間粘結(jié)性能的影響規(guī)律。通過(guò)與已有成果的對(duì)比,驗(yàn)證了本文所推導(dǎo)公式的正確性。計(jì)算結(jié)果表明,在短期荷載作用下,采用瀝青基灌漿材料灌漿的后張預(yù)應(yīng)力結(jié)構(gòu)可按有粘結(jié)預(yù)應(yīng)力結(jié)構(gòu)進(jìn)行計(jì)算,在長(zhǎng)期荷載作用下,需按無(wú)粘結(jié)預(yù)應(yīng)力結(jié)構(gòu)進(jìn)行計(jì)算。
[Abstract]:In the post tensioning system of civil engineering, the slurry is the last line of defense to ensure that the prestressing tendons are not corroded. The grouting effect of the prestressing force is to protect the prestressed reinforcement and provide the bond between the prestressed reinforcement and the concrete around the pass. The premise is that the prestress channel is completely filled by the slurry. Full, but the presence of water in the slurry makes it very difficult to complete the grouting of the channel, and the failure of the pore grouting is a problem in the post tensioning system. In this paper, two measures to prevent and control the bleeding of the grouting are put forward, and the grouting is focused on the substitute of the cement based material instead of the bituminous base material. The application of asphalt based grouting technology in the post tensioned prestressed structure is realized through the study of the mixture ratio of materials, irrigability, the influence of the loss of prestress and the bonding performance of prestressing tendons. The main contents and achievements of this paper are as follows: (1) the grouting test knot of the existing grouting technology and material The results show that the grouting is not dense in the prestress channel. The process of water secretion and the measures to reduce the bleeding are discussed. In order to improve the structure level of the prestress channel, a combination of rubber bars is developed to form the prestress channel of the belt pass, and the mechanism to solve the harm of the bleeding of the slurry is studied. On the basis of the prototype of the simple supported box beam of road 32m, a full scale grouting compactness test was designed and carried out. Combined with the test, the characteristics of the production, transmission and distribution of the slurry in the channel were analyzed, and the influence of the height of the pass on the density of the grouting was studied. The experimental results showed that the use of the pass through the pass can make the slurry secreted. The hole formed by the water is separated from the prestressed reinforcement to avoid the corrosion of the prestressing tendons. For the post tensioned structure, the grouting density of the tunnel with the pass is far superior to the circular channel. (2) the setting target and the test plan of the asphalt base grouting material are determined. After preliminary test, it has been determined. The asphalt based asphalt is modified bitumen. On the basis of the addition ratio of 12.5%., the mixture ratio of asphalt based grouting material is obtained by the viscosity test of different mixture ratio asphalt base grouting material and the shear strength test. The mixture ratio of asphalt base grouting material is: matrix asphalt + rock bitumen (12.5%) + (40%) (cement: cement) (40%). The shear strength of the asphalt based grouting material at normal temperature is 697.21 kPa, and its irrigation temperature should be higher than 115. In order to increase the dosage of lime and add fiber, the mixture ratio of the improved asphalt base grouting material is: matrix asphalt + rock bitumen (12.5%) + (water sludge =3:7) (40%) + fiber (1%), and the improved asphalt base grouting The shear strength of the material is about 2 times that of the common type, and its irrigation temperature should be higher than 140. (3) the theoretical calculation formula of the convection heat transfer coefficient of the asphalt based material in the pass is derived. The finite element model of the grouting test beam is established. The key parameters of the grouting process are determined by the simulation calculation of the grouting process. The appropriate grouting flow rate is 50 L/. Min, the reasonable grouting temperature is: the inlet temperature is 160, the wall temperature is 60, and the appropriate grouting pressure is 0.8 MPa. through the field grouting test of the test beam and the external prestressed concrete pass. The correctness of the grouting process parameters and the effectiveness of the grouting effect are verified. (4) through the use of asphalt base material irrigation. The calculation of the temperature field and stress field of the concrete beam of the slurry can be obtained. The pore forming material of the prestressed concrete pass should be selected as the HDPE material. The time of the grouting is the most important parameter affecting the temperature field and the stress field. Under the temperature degree of each slurry given in this article, the maximum tension of concrete is less than the prescribed value of the gauge. The error between the measured data and the measured data is less than 10%, and the error of the measured value of the stress field is less than 15%. It shows that the calculation results of this paper are accurate and effective. The applicability of the asphalt base material grouting is established, and the safety grouting time of different strength grade concrete under the different temperature is obtained. The post tensioning construction of asphalt based material can be used as a basis. (5) through the test, the mechanical properties of the prestressed steel strand under the slurry temperature can reach 0.9 times that of the original index. After the maximum stress relaxation can reach the 6.36%. slurry temperature, the mechanical properties can be restored to more than 0.965 times of the original index, and the stress relaxation is the greatest. Based on the test results, the mechanical properties degradation model and stress relaxation model of prestressed steel strand under and after the action of slurry temperature are obtained. The short-term and long term prestress loss model caused by the slurry temperature is established. The maximum error is 14.1% compared with the field prestress test results, which verifies the accuracy of the model. On the basis of the viscoelastic constitutive relation of asphalt based grouting material, the theoretical solution of bond stress of prestressed reinforcement and bituminous base material is derived by calculation. On the basis of the viscoelastic constitutive relation of asphalt based grouting material, the loss rate of long term prestress produced in the most unfavorable condition of asphalt base material grouting is 2.73%. (6). The stress of steel strand, steel strand matrix interface and asphalt base material base are obtained. The influence of the load, the radius ratio of the prestressed reinforcement and the matrix, the temperature of the bituminous material and the loading time on the bond performance between the prestressed reinforcement and the bituminous base material is discussed. The validity of the formula is verified by the comparison with the existing results. The calculation results show that the short-term load is used in the short term load. Under the action, the post tensioned prestressed structure using the grouting material of asphalt base grouting material can be calculated according to the bonded prestressed structure. Under the long term load, it is necessary to calculate the unbonded prestressed structure.
【學(xué)位授予單位】：北京交通大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：U444;U446
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本文編號(hào)：2028178