張國喜,李曉鐘
(蘭州交通大學(xué) 土木工程學(xué)院,甘肅 蘭州 730070,E-mail:395374064@qq.com)
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基于灰色關(guān)聯(lián)故障樹的運(yùn)營期隧道病害風(fēng)險(xiǎn)研究
張國喜,李曉鐘
(蘭州交通大學(xué) 土木工程學(xué)院,甘肅 蘭州 730070,E-mail:395374064@qq.com)
摘 要:隧道運(yùn)營期的管理決定了鐵路運(yùn)行的安全,為保證運(yùn)營安全,必須對(duì)隧道運(yùn)營期病害的風(fēng)險(xiǎn)進(jìn)行管理研究。用故障樹方法對(duì)隧道病害進(jìn)行分析,找出影響隧道運(yùn)營安全作為底事件,分析出故障樹系統(tǒng)任意一個(gè)底事件相關(guān)割集的重要度。利用灰色關(guān)聯(lián)的思想得出任意最小割集的關(guān)聯(lián)度,再依據(jù)關(guān)聯(lián)度得出需要重視的底事件(既有排水設(shè)施年久失修阻塞,材料強(qiáng)度下降,隧道內(nèi)照明不良),并提出具有針對(duì)性的管理改進(jìn)建議。
關(guān)鍵詞:隧道病害;灰色關(guān)聯(lián);故障樹;運(yùn)營期風(fēng)險(xiǎn);底事件
隨著經(jīng)濟(jì)的發(fā)展,人們對(duì)于出行提出了新的要求。2004年1月國務(wù)院頒布的中長期鐵路網(wǎng)規(guī)劃指出,建立省會(huì)城市間以及地區(qū)間如京津冀地區(qū)、長三角地區(qū)、環(huán)渤海灣地區(qū)和珠三角地區(qū)的城市快速鐵路系統(tǒng),到2020年全國鐵路運(yùn)營里程達(dá)到12萬km,實(shí)現(xiàn)“四縱四橫”鐵路總體布局。截止到2013年底,我國運(yùn)營的隧道達(dá)到11074座,受設(shè)計(jì)、施工、運(yùn)營環(huán)境、運(yùn)營時(shí)間等的影響,隧道病害日益嚴(yán)重[1]。目前隧道建設(shè)受氣候條件、地質(zhì)條件和設(shè)計(jì)要求等影響,建設(shè)難度增大。超長、超大跨徑和超強(qiáng)水壓隧道越來越多,使得后期隧道運(yùn)營維護(hù)難度加大,很多隧道出現(xiàn)了不同程度和各種各樣的病害。如水害、凍害、襯砌結(jié)構(gòu)破壞、襯砌材料劣化、附屬設(shè)施損壞以及洞口仰坡塌方落石等。隨著鐵路大提速后運(yùn)營時(shí)間的增長,隧道病害的探測和維護(hù)時(shí)間縮短,加重了隧道病害的發(fā)生。
目前已有學(xué)者對(duì)上述問題進(jìn)行了相關(guān)研究,如曾水長[2]針對(duì)具體的病害給出了對(duì)應(yīng)的整治方法。袁超等[3]提出了隧道的劣化機(jī)制并根據(jù)劣化等級(jí)給出了整治方法。唐亮[4]對(duì)隧道襯砌結(jié)構(gòu)的風(fēng)險(xiǎn)和可靠性進(jìn)行了研究,建立了襯砌結(jié)構(gòu)系統(tǒng)建設(shè)期風(fēng)險(xiǎn)估計(jì)的模型,研究了各風(fēng)險(xiǎn)因素對(duì)襯砌結(jié)構(gòu)系統(tǒng)的影響程度的大小。從目前的研究現(xiàn)狀可以看出,隧道運(yùn)營期的風(fēng)險(xiǎn)分析比較缺乏,因此,本文主要對(duì)運(yùn)營期的隧道病害進(jìn)行風(fēng)險(xiǎn)研究,建立隧道運(yùn)營期病害風(fēng)險(xiǎn)估計(jì)模型,根據(jù)風(fēng)險(xiǎn)重要度分析,找出各種因素對(duì)隧道運(yùn)營的影響程度大小,為今后隧道維護(hù)提供借鑒。
通過大量閱讀隧道運(yùn)營期病害及病害整治方法的文獻(xiàn)[5~8],以及對(duì)沈陽鐵路局管轄的226座隧道探測得到的數(shù)據(jù)[4](見圖1),構(gòu)建了運(yùn)營期隧道病害的故障樹模型如圖2所示。
圖1 運(yùn)營隧道病害統(tǒng)計(jì)
圖2 運(yùn)營期隧道病害的故障樹模型
建立了隧道運(yùn)營期故障樹。頂事件是指故障樹系統(tǒng)中最不希望發(fā)生的事件,因此把隧道運(yùn)營安全事故(中斷或停運(yùn))作為頂事件,用T表示。對(duì)故障樹系統(tǒng)進(jìn)行分析,造成頂事件T發(fā)生的事件有:A1(滲漏水或凍害)、A2(襯砌結(jié)構(gòu)破壞)、A3(附屬設(shè)施破壞)和X16(洞口仰坡塌方落石)。
對(duì)A1進(jìn)行分析可知,X1(既有排水設(shè)施包括襯砌背后的暗溝、盲溝、無襯砌輔助坑道、排水孔和暗槽等年久失修阻塞)、X2(地區(qū)氣溫)、X3(圍巖凍脹性)、X4(邊墻下部排水孔周邊及暗渠式排水孔周邊圍巖會(huì)產(chǎn)生超過固有限界流速的水,對(duì)周圍軟弱圍巖滲透和沖刷)均可能會(huì)引起滲漏水或凍害。
對(duì)A2進(jìn)行分析可知[9],B1(螺栓接頭事故)、B2(管片破壞)、B3(密封墊損壞)都可能會(huì)造成襯砌破壞。其中X5(螺栓質(zhì)量缺陷)、X6(螺栓剪力破壞)、X7(螺栓腐蝕)都可能會(huì)造成B1(螺栓接頭事故)的發(fā)生。X8(管片質(zhì)量缺陷)、X9(水土壓力增大)、X10(材料強(qiáng)度下降)都可能會(huì)造成B2(管片破壞)的發(fā)生。X11(密封墊材料老化)、X12(腐蝕作用)都可能會(huì)造成B3(密封墊損壞)的發(fā)生。
對(duì)A3進(jìn)行分析可知,X13(洞內(nèi)外排水電子系統(tǒng)損壞)、X14(隧道內(nèi)通風(fēng)不良)、X15(隧道內(nèi)照明不良)都可能會(huì)造成A3(附屬設(shè)施破壞)的發(fā)生。
2.1 灰色關(guān)聯(lián)故障樹的基本原理
故障樹系統(tǒng)中,若干個(gè)底事件發(fā)生就會(huì)導(dǎo)致頂事件發(fā)生,這些事件的集合稱為割集C,表示為{x1,x2,x3........xn},設(shè)xi表示底事件的狀態(tài)變量,當(dāng)割集C中取消任意一個(gè)狀態(tài)變量xj,頂事件不發(fā)生,則稱割集C為最小割集。故障樹系統(tǒng)中,假設(shè)有m個(gè)底事件,n個(gè)最小割集,系統(tǒng)中包含第i個(gè)底事件的最小割集數(shù)記為gi[Q( t )],可以定義第i個(gè)底事件的相關(guān)割集重要度為,此時(shí)可以得到m個(gè)底事件的相關(guān)割集重要度的向量I={I1,I2,I3,....,Im}。
灰色關(guān)聯(lián)的思想是建立一個(gè)理想狀態(tài)的標(biāo)準(zhǔn),將待檢驗(yàn)狀態(tài)與理想狀態(tài)進(jìn)行關(guān)聯(lián),找出關(guān)聯(lián)度大的待檢驗(yàn)狀態(tài)。假設(shè)第ni個(gè)最小割集Li含有mi個(gè)底事件,則可以構(gòu)建一個(gè)理想狀態(tài)下的矩陣[10]:
灰色關(guān)聯(lián)故障樹就是要將底事件的相關(guān)割集重要度向量I與理想狀態(tài)矩陣L進(jìn)行關(guān)聯(lián),找出關(guān)聯(lián)度大的最小割集。而這一關(guān)聯(lián)度大的最小割集就是隧道運(yùn)營期可能出現(xiàn)病害的主要原因,為實(shí)際維護(hù)提供必要參考依據(jù)。
2.2 灰色關(guān)聯(lián)故障樹的應(yīng)用過程
2.2.1 求底事件發(fā)生的概率
根據(jù)所建立的故障樹,對(duì)16個(gè)底事件發(fā)生概率的求解分為3種方法:
(1)調(diào)查法。以沈丹線為例,沈丹線西起遼寧省沈陽市,東到遼寧省丹東市,屬沈陽鐵路局管轄內(nèi)主要線路之一。調(diào)查數(shù)據(jù)顯示,沈丹線的47座隧道中,有8座出現(xiàn)照明不良,6座隧道通風(fēng)不良,21座隧道洞內(nèi)外排水設(shè)施損壞。11處(長度約675.5 m)出現(xiàn)洞口仰坡坍方落石現(xiàn)象[3]。
(2)計(jì)算法。基于可靠度理論的襯砌結(jié)構(gòu)損壞的失效概率計(jì)算方法,運(yùn)用ANSYS軟件計(jì)算底事件發(fā)生的概率[4]。
(3)專家打分法[11]。邀請(qǐng)專家對(duì)底事件的失效概率進(jìn)行打分,打分依據(jù)如表1、表2所示。
表1 底事件發(fā)生的嚴(yán)重度A
表2 底事件發(fā)生的可能度B
由專家打出嚴(yán)重度A和可能度B的分?jǐn)?shù),通過P=(A+B)×0.5計(jì)算得出。
通過3種方法可以得出16個(gè)底事件的失效概率,見表3。
表3 底事件失效概率
2.2.2 求解最小割集
對(duì)故障樹系統(tǒng)用上行法或者下行法,可以求得使頂事件發(fā)生的最小割集L,研究最小割集L可以得到系統(tǒng)的最薄弱環(huán)節(jié),以便后續(xù)改進(jìn)。設(shè)系統(tǒng)的結(jié)構(gòu)函數(shù)為φ(X)=φ(x1,x2,x3........xn),結(jié)構(gòu)函數(shù)表示了最小割集和頂事件的關(guān)系。
與門連接的系統(tǒng):
或門連接的系統(tǒng):根據(jù)建立的運(yùn)營期隧道故障樹系統(tǒng)的結(jié)構(gòu),可以得到該系統(tǒng)的結(jié)構(gòu)函數(shù):
由此可得運(yùn)營期隧道故障樹系統(tǒng)的最小割集,即16個(gè)底事件分別都是一個(gè)最小割集,得到的理想狀態(tài)下的矩陣:
2.2.3 求解相關(guān)割集重要度向量
若故障樹系統(tǒng)含有ci個(gè)最小割集,且它們相互獨(dú)立,則頂事件失效的概率在計(jì)算中可以通過下列公式得出頂事件的失效概率:
式中,Pi表示最小割集;ci為發(fā)生的概率。
本系統(tǒng)中16個(gè)底事件分別都是一個(gè)最小割集,由此可以得出頂事件發(fā)生的概率P(T)=0.9930,則第i個(gè)底事件的相關(guān)割集重要度為其中g(shù)[Q(t)]=P(T),可以得到16個(gè)底事件的相關(guān)割集重要度的向量I={I1,I2,I3,.... I16},見表4。
表4 相關(guān)割集重要度
I=(0.4532,0.4028,0.3525,0.2014,0.1511,0.1511,0.1007,0.1511,0.1511,0.4532,0.1007,0.1007,0.1712,0.1309,0.4532,0.2316)=3.9579
2.2.4 對(duì)I做歸一化處理得
I=(0.1654,0.1018,0.0891,0.0509,0.0382,0.0382,0.0254,0.0382,0.0382,0.1145,0.0254,0.0254,0.0433,0.0331,0.1145,0.0585)
2.2.5 求序列差
用歸一化后的I與理想狀態(tài)矩陣L每一行相減取正,得到序列差如下:
Δ1=(0.8346,0.1018,0.0891,0.0509,0.0382,0.0382,0.0254,0.0382,0.0382,0.1145,0.0254,0.0254,0.0433,0.0331,0.1145,0.0585)
Δ2=(0.1654,0.8982,0.0891,0.0509,0.0382,0.0382,0.0254,0.0382,0.0382,0.1145,0.0254,0.0254,0.0433,0.0331,0.1145,0.0585)
Δ3=(0.1654,0.1018,0.9109,0.0509,0.0382,0.0382,0.0254,0.0382,0.0382,0.1145,0.0254,0.0254,0.04 33,0.0331,0.1145,0.0585)
Δ4=(0.1654,0.1018,0.0891,0.9491,0.0382,0.0382,0.0254,0.0382,0.0382,0.1145,0.0254,0.0254,0.0433,0.0331,0.1145,0.0585)
Δ5=(0.1654,0.1018,0.0891,0.0509,0.9618,0.0382,0.0254,0.0382,0.0382,0.1145,0.0254,0.0254,0.0 433,0.0331,0.1145,0.0585)
Δ6=(0.1654,0.1018,0.0891,0.0509,0.0382,0.9618,0.0254,0.0382,0.0382,0.1145,0.0254,0.0254,0.0433,0.0331,0.1145,0.0585)
Δ7=(0.1654,0.1018,0.0891,0.0509,0.0382,0.0382,0.9746,0.0382,0.0382,0.1145,0.0254,0.0254,0.0433,0.0331,0.1145,0.0585)
Δ8=(0.1654,0.1018,0.0891,0.0509,0.0382,0.0382,0.0254,0.9618,0.0382,0.1145,0.0254,0.0254,0.0433,0.0331,0.1145,0.0585)
Δ9=(0.1654,0.1018,0.0891,0.0509,0.0382,0.0382,0.0254,0.0382,0.9618,0.1145,0.0254,0.0254,0.0433,0.0331,0.1145,0.0585)
Δ10=(0.1654,0.1018,0.0891,0.0509,0.0382,0.0382,0.0254,0.0382,0.0382,0.8855,0.0254,0.0254,0.0433,0.0331,0.1145,0.0585)
Δ11=(0.1654,0.1018,0.0891,0.0509,0.0382,0.0382,0.0254,0.0382,0.0382,0.1145,0.9746,0.0254,0.0433,0.0331,0.1145,0.0585)
Δ12=(0.1654,0.1018,0.0891,0.0509,0.0382,0.0382,0.0254,0.0382,0.0382,0.1145, 0.0254,0.9746,0.0433,0.0331,0.1145,0.0585)
Δ13=(0.1654,0.1018,0.0891,0.0509,0.0382,0.0382,0.0254,0.0382,0.0382,0.1145,0.0254,0.0254,0.9567,0.0331,0.1145,0.0585)
Δ14=(0.1654,0.1018,0.0891,0.0509,0.0382,0.0382,0.0254,0.0382,0.0382,0.1145,0.0254,0.0254,0.0433,0.9669,0.1145,0.0585)
Δ15=(0.1654,0.1018,0.0891,0.0509,0.0382,0.0382,0.0254,0.0382,0.0382,0.1145,0.0254,0.0254,0.0433,0.0331,0.8855,0.0585)
Δ16=(0.1654,0.1018,0.0891,0.0509,0.0382,0.0382,0.0254,0.0382,0.0382,0.1145,0.0254,0.0254,0.0433,0.0331,0.1145,0.9415)
2.2.6 求序列差最大值Δmax和最小值Δmin
根據(jù)上述Δi,i=1,2,3......16,可以得出序列差最大值和最小值:Δmax=0.9746,Δmin=0.0254。
2.2.7 求關(guān)聯(lián)系數(shù)
關(guān)聯(lián)系數(shù)由下式計(jì)算得出:
式中,ρ一般取0.5;Δij表示第i中的第j個(gè)元素。計(jì)算的關(guān)聯(lián)系數(shù)見表5。
2.2.8 計(jì)算關(guān)聯(lián)度
通過下列公式計(jì)算得出關(guān)聯(lián)度,見表6。
根據(jù)計(jì)算結(jié)果排序得出:
由此可得底事件X1(既有排水設(shè)施包括襯砌背后的暗溝、盲溝、無襯砌輔助坑道、排水孔和暗槽等年久失修阻塞)、X10(材料強(qiáng)度下降)、X15(隧道內(nèi)照明不良)是隧道運(yùn)營期故障樹系統(tǒng)的薄弱環(huán)節(jié),隧道運(yùn)營維護(hù)時(shí)應(yīng)高度重視。
(1)加強(qiáng)對(duì)排水設(shè)施的維修更換。水害是隧道運(yùn)營期常見的病害,所謂“十隧九害”正是反映了水害多發(fā)性。隧道設(shè)計(jì)過程中因地制宜的采用了“截、排、堵相結(jié)合”的原則,根據(jù)這一原則可以看出,隧道運(yùn)營期維護(hù)應(yīng)該做好“排”的工作,每隔一段時(shí)間有針對(duì)性地重點(diǎn)巡查排水設(shè)施,發(fā)現(xiàn)因泥沙或雜質(zhì)阻塞的排水設(shè)施及時(shí)清理,遭到破壞的排水設(shè)施及時(shí)維修更換,確保排水設(shè)施性能良好。
表5 關(guān)聯(lián)系數(shù)表
表6 關(guān)聯(lián)度
(2)早發(fā)現(xiàn)早治理。隨著運(yùn)營時(shí)間增長,隧道襯砌受到水害、凍脹和材料自身等原因的影響,材料強(qiáng)度下降,整體老化嚴(yán)重,造成襯砌開裂、脫落等病害,嚴(yán)重的甚至襯砌整體垮塌,造成運(yùn)行安全事故。因此平時(shí)營運(yùn)排查時(shí),對(duì)發(fā)現(xiàn)的襯砌滲水引起注意,查明滲水原因,制定治理方案,對(duì)老化和腐蝕嚴(yán)重的部位剔除干凈,將周圍混凝土鑿毛,沿裂縫兩側(cè)注漿。
(3)優(yōu)化隧道內(nèi)部環(huán)境。隧道內(nèi)部空間狹小,照明不良和通風(fēng)不良給排查人員的排查工作帶來了不便,甚至影響排查的結(jié)果,對(duì)一些潛在的病害不能及時(shí)發(fā)現(xiàn),錯(cuò)過了最佳的治理時(shí)間。
對(duì)隧道運(yùn)營期病害的風(fēng)險(xiǎn)管理,是實(shí)現(xiàn)鐵路安全運(yùn)行的關(guān)鍵。本文通過建立灰色故障樹模型,對(duì)影響隧道安全的風(fēng)險(xiǎn)進(jìn)行了識(shí)別和評(píng)價(jià),找出了隧道運(yùn)營期安全的薄弱環(huán)節(jié),針對(duì)這些薄弱環(huán)節(jié)提出了加強(qiáng)對(duì)排水設(shè)施的維修更換、早發(fā)現(xiàn)早治理、優(yōu)化隧道內(nèi)部環(huán)境的建議。
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張國喜(1991-), 男,碩士研究生,研究方向:土木工程建造與管理;
李曉鐘(1976-), 男,副教授,碩士生導(dǎo)師,研究方向:土木工程建造與管理。
Application of Gray Correlation Fault Tree on Risks of the Defects of the Operational Tunnel
ZHANG Guo-xi,LI Xiao-zhong
(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China,E-mail:395374064@qq.com )
Abstract:Management of the operational tunnel determines the safety of the railway. In order to ensure the safety of operation,
risks of the defects of the operational tunnel must be controlled. Firstly,utilizing the method of fault tree,the tunnel defects are analyzed and found out the factors which affect the safety of the tunnel as the bottom events. Secondly, the importance of the correlation of the cut set is obtained. Finally,according to the grey relation,the great important minimum cut sets of the bottom events including existing drainage facility out of repair and block,reduction in strength of material,the tunnel poor lighting.
Keywords:tunnel defects;gray correlation;fault tree;operate risk;bottom events
作者簡介:
收稿日期:2015-11-04.
中圖分類號(hào):U451
文獻(xiàn)標(biāo)識(shí)碼:A
文章編號(hào):1674-8859(2016)01-077-05
DOI:10.13991/j.cnki.jem.2016.01.014