Studies on the risk evaluation of landslide geological disaster in Wulong County

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1 Avalable ole.ocpr.com Joural of hemcal ad Pharmaceutcal Research, 205, 7(5): Research Artcle ISSN : ODEN(USA) : JPR5 Studes o the rsk evaluato of ladslde geologcal dsaster Wulog outy Shuhu Jag ad Nae L 2,3 Departmet of ostructo Egeerg, hogqg ostructo Egeerg Vocatoal ollege, hogqg, ha 2 ollege of Resources ad Evromet, Southest Uversty, hogqg, ha 3 hogqg Egeerg Techology Research eter for Iformato Maagemet Developmet, hogqg Techology ad Busess Uversty, hogqg, ha ABSTRAT The rsk evaluato of Regoal ladslde geologcal dsaster s based o collecto, aalyss ad processg the ladslde geologcal dsasters ad the relatoshp betee fluecg factors, usg GIS platform ad techology, buld approprate mathematcal evaluato model, calculate the degree of rsk of each evaluato ut, ad the dvded to correspodg level of rsk, ad aalyss of regoal geologcal dsasters rsk zog.[]ths artcle assumed that the study area s a certa herarchy ad ucerta system. The herarchcal aalyss model s adopted to establsh the mpact factor of evaluato dex system, o the eght of each fluece factor of ladslde rsk quattatve aalyss, Also, through the overlay aalyss fucto of GIS for ladslde rsk evaluato ad zog for qualtatve aalyss. Key ords: ulog, ladslde geologcal dsaster, rsk evaluato INTRODUTION Purpose of the rsk evaluato of ladslde geologcal dsaster s based o thorough vestgato ad study,through the aalyss ad research to determe the desty, stregth ad ladslde occurrece probablty ad may cause ury zoe of the locato, rage, ad the damage degree rak, provde the foudato for the further evaluato of dsaster losses ad preparg for dsaster rsk assessmet [-2]. The rsk evaluato of ladslde geologcal dsaster s the ma meag for the govermet ad the geologcal dsaster maagemet departmet terms of prevetg dsaster ad dsaster mtgato provdes referece for decso-makg, so as to promote the sustaable developmet of local ecoomy ad socal stablty. The occurrece of ladslde geologcal dsasters maly cotrolled by to aspects reasos: teral cause ad exteral cause. Iteral cause maly refers to the ladform, geologc structure, fluecg factors of stratum lthology, such as exteral cause refers to the earthquake, the fluece of the rafall ad huma egeerg actvtes. Because of the fluece factors are fuzzy ad ucertaty, ad the complexty of the teracto betee all the factors may also exst, therefore, brgs certa dffculty to the rsk evaluato of ladslde research. Selectg the approprate mathematcal model s the key to the rsk evaluato of regoal geologcal dsaster ad regoalzato, Has a large umber of scholars use dfferet mathematcal model the study of the rsk evaluato of regoal geologcal dsaster ad regoalzato, Such as aalytc herarchy process (ahp), the amout of formato la, ut cluster aalyss, dscrmat aalyss method, fuzzy comprehesve evaluato method ad the eural etork model, etc. I ths study, because of the specal locato of the study area, the scope s larger, ad the research belogs to the typcal karst ladform, lead to geologcal dsasters rsk zog more fluecg factors. Therefore, ths artcle assumed that the study area s a certa herarchy ad ucerta system. The herarchcal aalyss model s adopted to establsh the mpact factor of 370

2 Shuhu Jag ad Nae L J. hem. Pharm. Res., 205, 7(5): evaluato dex system, o the eght of each fluece factor of ladslde rsk quattatve aalyss, Also, through the overlay aalyss fucto of GIS for ladslde rsk evaluato ad zog for qualtatve aalyss. EXPERIMENTAL SETION Ths research adopts AHP (Aalytc Herarchy Process) to establsh the model of the rsk evaluato of ladslde. Ths method s proposed by sate, a professor at uversty of Pttsburgh, used to solve herarchcal eghted decso aalyss. Based o the ature of the complex problems, fluece factors ad ts er lk aalyss, establsh to dffcult to quattatvely express the complex system decso-makg model ad method. Ths method s sutable for complex decso problem to make decsos but lack of quattatve formato. The rsk evaluato of Ladslde s a complex decso problem, partcpate the evaluato of the mpact factor s dffcult to quattatve expresso, so the aalytc herarchy process (ahp) as appled to the rsk evaluato of Ladslde ca overcome the problem of obectve exstece, acheved good results [3]. Basc steps of Aalytc Herarchy Process ()To ask questos ad to clear up problems clude the relatoshp betee the factors ad factors; (2) Set up the structure of the recursve order herarchy model; Problem the frst place herarchcal, a herarchcal structure model s costructed. I ths model, the research problem s broke to three levels, o a level of elemets as a crtero to the ext level related elemets domate role, these levels are geerally dvded to the follog three categores: ) at the top: the purpose of makg a decso or to solve the problem, also ko as the target layer; 2) the mddle ter: also ko as the crtero layer ad cotas a umber of volved to acheve the goal of the termedate lks, cludg those of eeded to cosder, the so; 3) bottom: cludg the measures for the realzato of the target selecto, decso scheme, etc., ad dex layer or soluto. (3) To costruct udgmet matrx To costruct udgmet matrx s a key lk the process of AHP aalytc herarchy model. the elemets of udgemet matrx value reflects the relatve mportace of varous factors, These udgmets are expressed by the troducto of approprate scale umercal represetato. Judgmet matrx s sad a layer of all factors relatve to the comparso of the relatve mportace of up a layer factors. U {,, } Suppose, 2 L, to compare the fluece of some factors U sze. To provde more relable data, e ca take the factor compare to establshed pared comparso matrx method [4].Where each takes to factors ad, the rato of the sze effect o U a s expressed by, all the comparso results th matrx ( ) A a Easy to see, f the rato of the sad, call A udgmet matrx betee U ad (table). ad Table The fluece factors of udgemet matrx A 2 a a 2 a 2 a2 a 22 a 2 a3 a 32 o U s / a. O ho to determe the value of the T.Satty -9 scale meas. s fluece o U s a a,the the rato of the ad s fluece a, referece Numbers to 9 ad ts verse scale, Table 2 lsts 37

3 Shuhu Jag ad Nae L J. hem. Pharm. Res., 205, 7(5): Table2 The elemets of udgemet matrx assgmet stadard a defe a defe ad 3 are equally mportat 2 Betee equally mportat ad slghtly more mportat slghtly more mportat tha obvously mportat tha 5 4 Betee slghtly ad obvously mportat 6 Betee clearly ad obvously mportat 7 clearly mportat tha 8 Betee apparet ad absolute mportat 9 absolutely mportat tha lassfcato too much creased the dffculty of udgemet, beyod people's udgmet, geerally do ( - ) / 2 tmes to udgmet s ecessary. (4)Judgmet matrx cosstecy check To costruct udgmet matrx, because of the complexty of the obectve thgs ad the partal uderstadg of the problem, may be the cause of cosstecy matrx devato s too large, t ll lead to varous factors dex eght dstrbuto s ot reasoable, therefore, eed a cosstecy check of udgmet matrx [5]. osstecy check process: for every udgmet matrx calculatg maxmum egevalues ad correspodg egevectors, ad the calculate the cosstecy dex, cosstecy dex ad cosstecy rato, oly he the radom cosstecy rato (R < 0.0), the cosstecy of udgemet matrx have satsfed. The rsk evaluato herarchy model of Ladslde geologcal dsaster Through the establshmet of the rsk evaluato herarchy model of ladslde geologcal dsaster, aalyse the eghts of ladslde geologcal dsaster mpact factors. The ma fluecg factors of ladslde ere teral factors ad exteral factors the study area. Iteral factors clude: the topography, geologcal structure, stratum lthology; Exteral factors clude: rafall, rvers, vegetato coverage, huma actvty. Addtoally accordg to ladslde formato mechasm ad repeatablty characterstcs of ladslde, the study area should be cosdered ladslde remote sesg survey of geologcal hazard, amely to study the effect of ladslde dsaster the area desty ad scale. Based o ths, to determe the study of the ma factors to fluece factor of ladslde dsaster the area, the herarchy structure model s establshed. Accordg to the structure model, I ulog couty, the evaluato herarchy model of Ladslde geologcal dsaster factor U {teral factors U, exteral factors U2, hstorcal codtos U3}. Amog them: Iteral factors U {topography factor, geologcal structure factor2, formato lthology factor 3}; Exteral factors U2 {aual rafall 4, to rvers from 5, vegetato coverage 6, huma actvtes 7}; Hstorcal codto U3 { ladslde desty 8, ladslde scale 9}; To costruct udgmet matrx Through the comparso of all these factors, to establsh the ladslde fluece evaluato dex of udgmet matrx ad the relatve mportace of each dex the study area.as table 3, table 4,table 5, table 6. Table3 The udgmet matrx of rsk factors ad relatve mportace scale U Iteral factors U Exteral factors U2 Hstorcal codto U3 Iteral factors U /2 Exteral factors U2 /2 /2 Hstorcal codto U3 2 2 Table4 The udgmet matrx of teral factors ad relatve mportace scale U topography geologcal structure 2 formato lthology 3 topography /3 2 geologcal structure formato lthology 3 /2 /5 372

4 Shuhu Jag ad Nae L J. hem. Pharm. Res., 205, 7(5): Table5 The udgmet matrx of exteral factors ad relatve mportace scale U2 aual rafall 4 to rvers from 5 vegetato coverage 6 huma actvtes 7 aual rafall /5 to rvers from 5 /2 2 /7 Vegetato coverage 6 /4 /2 /8 huma actvtes Table6 The udgmet matrx of hstorcal codtos ad relatve mportace scale U3 ladslde desty 8 ladslde scale 9 ladslde desty 8 /2 ladslde scale 9 2 The cosstecy check of udgmet matrx ()To determe the relatve eght coeffcet Accordg to the udgmet matrx, proceed herarchy sgle sorts ad herarchy total sorts, ad the to determe the evaluato factors ad evaluato dex eghts. Herarchy sgle sorts s amed at ths layer factors mportace, The eght value of Herarchcal sgle sorts ca be obtaed by solvg the egevalue, that s: I the above formula: A s the udgmet matrx, vector of A, W s correspodg eght value of the sgle sort elemet levels. λ max AW λ W max () s the maxmum characterstc root of A,W s feature For example, sho cosstecy check of udgmet matrx of teral factors fluecg matrx U. alculato process s as follos: ( ), c c c c,,2, L, (2) 3 / 2 /3 /5 2 5 ; ; Accordg to the le together: W ; [ ] T, 2, L, W, [, 2, ] T W,, L W c ; (3) (4) Through the above calculato,the eght vector of the sgle sort for udgmet matrx of teral factors U: 373

5 Shuhu Jag ad Nae L J. hem. Pharm. Res., 205, 7(5): W I the same ay,the eght vector of the sgle sort for udgmet matrx of exteral factors U2: 0.000, the eght vector of the sgle sort for udgmet matrx of hstorcal codto W U3: W 3, the eght vector of the sgle sort for udgmet matrx of U: W T (2) osstecy check Get W from the above to calculato, as a bass for the loer elemets to the upper oe, eed to check the cosstecy of udgemet matrx. λ max a (5) Accordg to the formula (5),to calculate the feature vector of trsc factor U s udgmet matrx / / / λ max Through the above method to costruct udgmet matrx, hch ca reduce the terferece of other factors, more obectvely reflect the dfferece betee a par of factor fluece. Judgmet matrx provded by the decso makers a cosstecy check are ecessary, to decde hether to accept t. The steps of cosstecy check are as follos: ) alculate the cosstecy dex I. I λ max - (6) I λ. - 3 max Accordg to the formula (6) s obtaed: ) To fd the correspodg average radom cosstecy dex RI, as sho table 7. Table7 orrespodg RI values of N order matrces RI ) alculate the cosstecy rato R R I RI 0.58 R < 0.0, Thk teral factors the cosstecy of udgmet matrx U s acceptable, otherse the udgmet matrx should be ameded. 374

6 Shuhu Jag ad Nae L J. hem. Pharm. Res., 205, 7(5): I the same ay, e ca obta exteral factors udgmet matrx U2 ad hstorcal stuato factors udgmet matrx U3. The calculato results ad coclusos are sho table 8. Table8 osstecy check results ad coclusos Matrx the cosstecy dexi the cosstecy rator coclusos U satsfacto U satsfacto U3 Secodary matrx are alays satsfactory cosstecy U satsfacto To sum up, accordg to the actual stuato, usg the herarchcal aalyss method, to determe the effect of geologc dsaster dager evaluato factors the study area eght coeffcet, the structure of the cosstecy of udgmet matrx s satsfed, the relatve mportace attached to score betee varous factors s feasble. (3) alculate the cosstecy rato of the eght of each evaluato factor coeffcet for total orderg. Herarchy total sequecg calculato formula: I the above formula: A U W (7) W s sgle sortg eght of each evaluato factor (secodary factors) level, U s sgle sortg eght of each evaluato factor (prmary factors) level, A s total order eght of each evaluato dex. Usg the formula (7), ca be calculated for each to fluece the outcome of total sorts of dex eghts. The results are sho table 9. Table9 Each evaluato factor eght total sorts U U U2 U3 Total order sortg eght coeffcet U W topography geologcal structure formato lthology aual rafall to rvers from Vegetato coverage huma actvtes ladslde desty ladslde scale Accordg to the total sorts, the sze of the exstg geologcal dsaster, the desty dstrbuto of geologcal dsasters, the fluece factors of huma actvtes s the most serous. These factors for the occurrece of ladslde geologcal dsasters play a mportat role. RESULTS AND DISUSSION The rsk evaluato of Regoal ladslde geologcal dsaster ad regoalzato Ths artcle used the Regular or rregular grd ut to dvde the study area. Specfc evaluato usg aalytc herarchy process (ahp) combed th GIS techology to calculate each assessmet ut of geologcal dsaster rsk dex, ad rsk zog map the study area s obtaed. Rsk dex calculato model expressos: I the above formula: Q v (8) Q s the rsk dex of ut, Degree of geologcal dsaster rsk factor score of. s the eght of geologcal hazard factors, v s the 375

7 Shuhu Jag ad Nae L J. hem. Pharm. Res., 205, 7(5): The fluece factors of affectg the geologcal dsaster evaluato factors, ad must be edoed th quattatve values. For each ut of all geologcal hazard factor score of expert experece method s used to quatfed expresso, level 4 pots method [6]. Accordg to the actual stuato the study area combed th the expert experece, the fluece factor of ladslde hazard assgmet are lsted table 0. Table0 Expert ratg assgmet of mpact factor ladslde The mpact factor of ladslde value value mplcato topography Small effect geologcal structure 2 Geeral effect formato lthology 2 Geeral effect aual rafall 3 Medum effect to rvers from 3 Medum effect Vegetato coverage Small effect huma actvtes 4 Strog effect ladslde desty 4 Strog effect ladslde scale 3 Medum effect Through formula (9), usg GIS softare MAPGIS, ll calculate the eght value of factors ad the fluecg factors of value by the map algebra operato, grd ca be obtaed the fal score value of evaluato ut. Accordg to the fal score value of grd evaluato uts ll rsk zog the study area to fve levels: very hgh dager zoe, hgh dager zoe, medum dager zoe, lo dager area, o dager zoe. Usg MAPGIS softare the spatal aalyss module (DTM), to extract the geologcal dsaster rsk dex of each ut after elmatg dscrete data, get the ladslde rsk of geologcal dsasters the study area comprehesve plae cotour map. I combato th the practcal stuato of the study area, accordg to the regoal rsk zog stadards, o the bass of the ladslde geologcal dsaster rsk comprehesve cotour map, the geologcal dsaster rsk s dvded to fve grades. The results are sho table. Accordg to the ladslde hazard cotour map, e ca get the ladsldes the study area geology dsaster rsk zog map, as sho fgure. Table Ladslde geologcal dsaster rsk herarchy table the study area Grade The value terval of cotour very hgh dager zoe >3.58 hgh dager zoe medum dager zoe lo dager area o dager zoe <.53 Fg. The zog map of ladslde rsk Wulog couty 376

8 Shuhu Jag ad Nae L J. hem. Pharm. Res., 205, 7(5): DISUSSION The zog map of ladslde rsk ad the remote sesg mage terpretato of ladslde geologcal locato are cosstet. Accordg to the research results to get the follog cocluso: () Hgh ladslde geologcal dsaster dager zoe ulog couty more cocetrated elevato 600 meters, obvous zoal dstrbuto, maly cocetrated uag rver coast lo valley area of mddle mouta ad ts ma trbutares especally uag rver, Sh Lag rver,dax rver area s the most serous. (2) Dfferet szes of ladslde geologcal dsaster dstrbuto rage s very de, strog dsperso, hgh rsk level. Very hgh dager zoe accouts for about 9.% of the couty area, hgh dager area accouted for 20.4% of the couty area, medum rsk area accouted for 24.4% of the couty area, lo dager area accouts for 33.% of the couty area, extremely lo dager area accouts for oly 3.0% of the couty area. (3) Frot ope slopes or to a zoal dstrbuto of lo ad mddle mouta slope zoe, ad hgh cut slopes or hgh fll to buld the ralay, hghay ad the structure of the slope slde s extremely hgh dager zoe ad hgh dager zoe. The area s the place that huma actvty s frequet, case of ladsldes, the loss ll be very serous. (4) Wulog couty the developmet of ladslde ad ts geologcal evromet s closely related to formato lthology the couty for the Jurassc, Perma ad Trassc shale, mudstoe, lmestoe ad sadstoe, ad are easy to slp strata th hgh sestvty, ad ulog couty hgh steep moutas, valleys ad cuttg, the geologcal codtos ad ladform rvers csed, uder the fluece of factors such as rastorm ad huma actvty, easy to ladsldes. I short, the overall ladslde of ulog couty ladslde area s de, strog dsperso, hgh rsk ratg, hgh strp of hgh-rsk groups of dager ad dstrbuto characterstcs. REFERENES []Xaodog L,etc. Joural of schua uversty (egeerg scece),200,42(5):83~9. [2]Xqu Xag,etc. Geography ad lad research,2002,8(3): [3]Yuaqag Lv,etc. Joural of ta sttute of urba costructo,2006,2(3): [4]Dogrog Xao,etc. Mcro computer formato, [5]Huapg Ouyag. outy of Tbet remote sesg ad GIS techology the applcato of the geologcal hazard vestgato ad evaluato. etral south uversty,200. [6]Jusog Sh,etc. Geologcal reve,2007,53(6):