發(fā)布時間：2018-03-11 18:41

  本文選題：GFRP抗浮錨桿　切入點(diǎn)：裸光纖光柵　出處：《青島理工大學(xué)》2015年博士論文　論文類型：學(xué)位論文

【摘要】：玻璃纖維增強(qiáng)聚合物(GFRP)錨桿是一種由樹脂和玻璃纖維復(fù)合而成的新型錨桿,與傳統(tǒng)的鋼筋錨桿相比,它具有比強(qiáng)度高、耐腐蝕性強(qiáng)、介電性好等優(yōu)點(diǎn),將GFRP材料引入抗浮錨桿體系,能夠克服傳統(tǒng)金屬錨桿存在的地下水腐蝕和電化學(xué)腐蝕等問題,特別適用于地鐵車站抗浮。本文借助于植入式裸光纖光柵傳感技術(shù)進(jìn)行一系列現(xiàn)場及室內(nèi)試驗(yàn),揭示了荷載作用下GFRP抗浮錨桿的應(yīng)力應(yīng)變分布規(guī)律及黏結(jié)破壞機(jī)理,獲得了GFRP抗浮錨桿與地基錨固(內(nèi)錨固)、與底板混凝土錨固(外錨固)的錨固性能及長期荷載作用下的蠕變特征,提出“全變形”的概念,完善了設(shè)計理論和方法。主要工作及研究成果如下:1、通過GFRP抗浮錨桿現(xiàn)場拉拔破壞性試驗(yàn),成功地將植入式裸光纖光柵傳感技術(shù)應(yīng)用于抗浮錨桿拉拔試驗(yàn)中,并與鋼筋抗浮錨桿進(jìn)行對比,研究風(fēng)化巖地基中GFRP抗浮錨桿內(nèi)錨固承載特征、荷載傳遞機(jī)制和界面黏結(jié)特性。研究表明:(1)GFRP抗浮錨桿的破壞形式有2種:短錨桿主要發(fā)生砂漿和圍巖界面(第二界面)剪切破壞,長錨桿主要在錨桿桿體和砂漿界面(第一界面)出現(xiàn)剪切破壞,其破壞實(shí)質(zhì)是桿體最大剪應(yīng)力處基體材料發(fā)生剪切破壞。(2)錨桿軸力沿深度方向逐漸遞減,并且超過一定深度后桿體不再受力;GFRP錨桿的應(yīng)力傳遞深度比鋼錨桿大,鋼錨桿的軸力沿深度衰減的速率比GFRP錨桿快。剪應(yīng)力的峰值隨荷載增加逐漸增大并向深部移動,但GFRP錨桿的剪應(yīng)力峰值比鋼筋錨桿大,鋼筋錨桿的剪應(yīng)力比GFRP錨桿發(fā)揮早。(3)錨固體介質(zhì)為M32.5水泥砂漿,錨固長度為2.0 m,直徑為28 mm的GFRP抗浮錨桿的極限抗拔承載力約為225 k N。對于直徑為28 mm和32 mm的GFRP抗浮錨桿,第一界面的平均黏結(jié)強(qiáng)度為1.50~1.54 MPa,第二界面的平均黏結(jié)強(qiáng)度為0.32~0.37 MPa,且第二界面平均黏結(jié)強(qiáng)度隨錨桿直徑的增加而增大。(4)GFRP抗浮錨桿的極限抗拔承載力隨錨桿直徑和錨固長度的增加而增大,一般均高于鋼筋抗浮錨桿。中風(fēng)化花崗巖地層中,GFRP抗浮錨桿的合理錨固長度建議取值為3.5~5.0 m。2、將螺母托盤錨具用于抗浮錨桿的外錨固,通過自行設(shè)計的室內(nèi)大型構(gòu)件對拉試驗(yàn),研究了不同錨固形式和不同錨固長度的GFRP抗浮錨桿的外錨固性能,對極限荷載作用下外錨固變形量(滑移量)及極限承載力進(jìn)行了測試。結(jié)果表明:(1)GFRP抗浮錨桿外錨固的破壞形式有2種:錨桿材料強(qiáng)度不足產(chǎn)生劈裂破壞;GFRP錨桿和混凝土界面相對滑移較大,產(chǎn)生拔出破壞。(2)對于直錨筋錨固和螺母托盤錨固的GFRP抗浮錨桿,外錨固長度為30d的極限承載力分別為356 k N、384 k N,比外錨固長度為15d的極限承載力分別提高65.6%、43.8%。對于不同錨固形式、相同錨固長度的GFRP錨桿,螺母托盤錨固的GFRP抗浮錨桿界面黏結(jié)強(qiáng)度比直錨筋錨固形式提高約7.9~24.4%。(3)GFRP抗浮錨桿與混凝土之間的平均黏結(jié)強(qiáng)度隨著外錨固長度的增加而降低,隨滑移量的增大而提高。(4)當(dāng)荷載水平低于200 k N時,直徑為28 mm、混凝土標(biāo)號為C25、外錨固長度為15d、30d的全螺紋GFRP抗浮錨桿,其外錨固變形量均不超過2.5 mm,能夠滿足工程需要。3、通過4根全長黏結(jié)螺紋GFRP抗浮錨桿在長期荷載作用下的拉拔蠕變試驗(yàn),研究了GFRP抗浮錨桿抗拔的蠕變力學(xué)模型,計算出模型中的蠕變參數(shù)并對模型的正確性進(jìn)行驗(yàn)證。引入時間損傷效應(yīng)的概念,結(jié)合蠕變力學(xué)模型推導(dǎo)出GFRP抗浮錨桿的長期抗拔力。研究表明:(1)GFRP抗浮錨桿在40%的極限荷載下才會發(fā)生蠕變,且蠕變變形較小。在實(shí)際工程中,40%左右的極限荷載能滿足在長期荷載下的抗浮要求。(2)Burgers力學(xué)模型能夠很好地描述GFRP抗浮錨桿的蠕變規(guī)律,模型預(yù)測結(jié)果與試驗(yàn)結(jié)果吻合較好。(3)基于損傷力學(xué)理論,結(jié)合Burgers模型推導(dǎo)了GFRP抗浮錨桿的損傷變量隨時間變化規(guī)律,并由此得到了GFRP錨桿抗拔承載力隨時間的變化規(guī)律,給出的GFRP抗浮錨桿的長期抗拔承載力與實(shí)際長期拉拔力相差不大,說明建立的蠕變損傷模型用于預(yù)測GFRP抗浮錨桿的長期抗拔承載力具有較好的適用性。4、在內(nèi)錨固、外錨固及蠕變試驗(yàn)的基礎(chǔ)上,分析論證了GFRP抗浮錨桿第一界面、第二界面及桿體材料的剪切破壞機(jī)制,并提出了“全變形”的概念,有助于深化對GFRP抗浮錨桿工作機(jī)制的認(rèn)識。
[Abstract]:Glass fiber reinforced polymer (GFRP) is a kind of new type of anchor bolt is composed of resin and glass fiber composites, compared with the traditional steel bolt, it has high strength, strong corrosion resistance, the advantages of good dielectric properties, the GFRP material is introduced into the anti floating anchor system can overcome the groundwater corrosion and electrochemistry the corrosion problems of traditional metal bolt, especially suitable for the subway station. A series of anti floating field and indoor tests on bare fiber grating sensing technology implanted with the help of revealing the anti floating anchor load under GFRP stress and strain distribution and bond failure mechanism, obtained the GFRP anti floating anchor and Anchor Foundation (within the anchorage, and concrete anchor) (Anchorage) creep characteristics of anchorage performance and long-term load, puts forward the concept of "whole deformation", improve the design theory and method. The main work and research The results are as follows: 1, through the GFRP anti floating anchor site drawing destructive test, successfully implanted bare fiber grating sensing technology used in anti floating anchor pullout test, and reinforcement of anti floating anchor comparison study on weathering characteristics of bearing GFRP anti floating anchor anchorage rock foundation, the load transfer mechanism and interfacial bond characteristics. The research showed that: (1) failure form of GFRP anti float anchor has 2 kinds: short bolt mainly interface mortar and surrounding rock (second interface) shear failure, long anchor bolt and mortar in the main interface (the first interface) to shear failure, the failure is the essence of the rod the maximum shear stress of matrix the material shear failure. (2) the bolt axial force decreases gradually along the depth direction and depth of rod body no longer force; GFRP anchor stress transfer depth ratio of steel bolt, steel bolt axial force along the depth attenuation rate than GFRP Bolt shear quickly. The peak stress increases with the increase of load and move to the deep, but the peak value of the shear stress of GFRP anchor bolt reinforced ratio, shear stress ratio GFRP steel anchor bolt played early. (3) the anchor solid medium for M32.5 cement mortar, the anchorage length is 2 m, diameter limit 28 mm GFRP anti floating anchor pullout capacity is about 225 K N. with diameter of 28 mm and 32 mm GFRP anti float anchor, average bond strength of the interface in the first 1.50~1.54 MPa, the average bond strength of second 0.32~0.37 interface for MPa, and the average bond strength of the second interface increased with the increase of bolt diameter increases. (4) increased with the increase of bolt diameter and anchorage length of the ultimate uplift capacity of anti floating anchor GFRP, are generally higher than the reinforced anti floating anchor. In weathered granite formation, anchoring length values of anti floating anchor GFRP 3.5~5.0 for m.2, the nut holder Anchorage anchorage disc for anti floating anchor, through indoor large components designed for tensile test, outer anchorage performance of different anchorage forms and different anchorage length GFRP anti floating anchor, anchor on the ultimate load under external deformation (displacement) and ultimate bearing capacity were tested. The results showed that (1): GFRP damage in the form of anti floating anchor anchorage has 2 kinds: the strength of bolt material problems of splitting failure; GFRP anchor and concrete interface slip greatly, produce pullout failure. (2) for the GFRP anchor bar and anchor nut tray anchoring anti floating anchor anchorage length is 30d the ultimate bearing capacity was 356 K N, 384 K N, the ratio of anchorage length 15d ultimate bearing capacity were increased by 65.6%, 43.8%. for different anchorage forms, GFRP the same bolt anchorage length, the bonding strength of GFRP anchor nut tray anti floating anchor interface Anchor bar anchorage forms increased by about 7.9~24.4%. (3) average bond strength between GFRP anti floating anchor and concrete decreased with the increase of anchorage length, increased with the amount of slip. (4) when the load level is lower than 200 K N, 28 mm in diameter, the concrete grade is C25, the outer anchorage length 15d, full thread GFRP 30d anti floating anchor, the outer anchorage deformation is less than 2.5 mm, can meet the needs of Engineering.3, floating anchor pullout creep test under long-term loading by 4 full length bonding thread GFRP anti creep mechanical model of anti floating anchor pullout resistance of the GFRP study, the calculated creep the parameters of the model and the correctness of the model is verified. By introducing the concept of time damage effect, combined with the creep mechanical model derived long-term pullout force of anti floating anchor GFRP. Research shows that: (1) GFRP in 40% of the anti floating anchor limit load under creep will occur Change, and the creep deformation is small. In practical engineering, the ultimate load of about 40% to meet the requirements of anti floating in the long-term load. (2) Burgers model can well describe the creep behavior of GFRP anti float anchor, the prediction results agree well with the experimental results. (3) based on the theory of damage mechanics the Burgers model is derived, combined with the law of damage variable GFRP anti float anchor changes with time, and the resultant GFRP anchor pullout capacity changes with time, the anti float anchor GFRP are long-term uplift bearing capacity and the actual long-term drawing force of little difference, that creep damage model for prediction of resistance floating anchor GFRP long-term uplift bearing capacity with.4, good applicability, anchoring, anchoring and creep tests based on analysis of anti floating anchor GFRP first machine interface, second interface and shear failure of rod material The concept of "full deformation" is put forward, which helps to deepen the understanding of the working mechanism of GFRP anti floating anchor.

【學(xué)位授予單位】：青島理工大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：TU476

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