Inothi elibalulekile lengcweti: Lesi sihloko siwukubuyekezwa kwezemfundo kwengobo yomlando futhi akusona isifundo se-geotechnical, izinga elabhorethri elivumelekile, ukubala kwesisekelo noma imanuwali yeziqondiso. Amagama okuqala, izinqubo, amayunithi okulinganisa, amanani, izigaba kanye nezinkomba “zemithetho yethu” yadluliswa ngaphandle kokuhlola ukuthotshelwa kwezindinganiso nemithethonqubo esebenzayo. Ukuhlolwa komhlabathi, ukukhetha kwendlela, ukuchazwa kwemiphumela kanye nezinqumo zokuklama kufanele kwenziwe ngochwepheshe abagunyaziwe be-geotechnical kanye nelabhorethri efanele yento ethile nendawo.
Isihloko sokuminyanisa umhlabathi asiyona ingxenye yomnikelo omusha womphakathi we-Savo Kusić. Ukugxila kokukhiqiza kwamanje kufaka amafasitela okhuni, amafasitela okhuni-aluminium kanye neminyango eyenziwe ngokwezifiso. Ngewindi elithile noma iphrojekthi yomnyango, ungathumela isicelo sekhotheshini.
Isisekelo sokuhlolwa kwe-edometer
Ukuminyanisa kwenhlabathi kunqunywa ukuhlolwa kokucindezelwa okuvimbelwe ukunwetshwa kwezinhlangothi, okubuye kubizwe ngokuthi i-oedometer test noma ukuhlolwa kokuqinisa.
Ukuhlolwa kwenziwa ngamasampula angaphazamiseki, futhi kwezinye izimo nakhona aphazamisekile. Esimweni sokuqala, isampula yokuhlola ithathwa ngokucindezela izindandatho zensimbi zibe isampula elikhudlwana, elingaphazanyiswa, elibese lifakwa ku-apparatus kanye neringi ngemva kokusika isampula eyeqile futhi ilinganisa indawo yayo ngamachopho esilinda. Esimeni sesibili, iringi igcwaliswa ngesampula esimweni sokuvumelana endaweni yokukhiqiza futhi kuleso simo yethulwa ku-oedometer.
Ukuhlola kwenziwa kusetshenziswa umshini owaqala ukwakhiwa uTerzaghi futhi wabizwa ngokuthi i-Oedometer. Namuhla, kunezinhlobo eziningana zokwakhiwa kwalesi sisetshenziswa, kodwa zonke zisekelwe esimisweni esifanayo, ukuhlola ukucindezelwa kwesampula yomhlabathi ngaphansi komthwalo ovinjelwe ukunwetshwa kwezinhlangothi.
I-Oedometer: incazelo yedivayisi
Fig. 1. Odometer
I-Oedometer iqukethe isilinda sensimbi lapho isampuli itholakala phakathi kwamatshe okuhlunga amabili (fig. 1). Isampula yethulwa kumshini wokusebenza ngeringi yensimbi enobubanzi obungu-7-10 cm kanye nobude obungu-1-4 cm. Umthwalo P udluliselwa kusampula ngetshe lokuhlunga elingaphezulu. Ngezansi kwetshe lesihlungi esingezansi, kunemigudu ngaphansi kwesilinda yokukhipha amanzi esampula eshubhu le-capillary, kanye nokuphakelwa kwamanzi. Njengoba ukucindezelwa kwesampula kwenziwa ngezindleko zama-pores, ngenxa yokuthi izinhlayiya zenhlabathi eqinile kanye namanzi e-pores cishe angenakulinganiswa, kuyadingeka ukuqinisekisa ukuthi amanzi aphuma kusampula ngesikhathi sokuhlolwa, okwenziwe ngetshe lokuhlunga, umzila kanye ne-capillary tube.
Ohlangothini lwesobunxele lwedivayisi kukhona ipayipi elihambisa amanzi elinompompi phambi kwesilinda, kuyilapho ishubhu le-capillary lingakwesokudla, nompompi ngemuva kwesilinda. Ishubhu le-capillary liphinde lisebenze ekunqumeni i-coefficient yenhlabathi yokungena k.
Ukuhlola
Lapho isampula lifakwa kusilinda futhi i-apparatus ihlanganiswa, vala umpompi wesokunxele, umphakeli wamanzi, futhi uvule umpompi ongakwesokudla, ukuze amanzi agelezele eshubhu le-capillary. Khona-ke umthwalo wesampula usondela, osetshenziswa kancane kancane. Imithwalo elandelayo ivame ukusetshenziswa:0,50;1,00;2,00;4,00;6,00kp/cm2futhi kuqhubeke kuze kufike ezingeni eliphakeme kakhulu lomhlabathi elilindelwe ngaphansi kwesakhiwo, ikakhulukazi kuze kufike10kp/cm2, futhi ngamadamu kungaba ngaphezulu20kp/cm2. Ezingeni ngalinye lomthwalo, ngesikhathi sokusetshenziswa, isitophuwashi siyaqalwa futhi ngezikhathi ezithile15“,30“,1’,2’,5’,15’,45’,2h5h24h, emva kwalokho njalo24h, kuze kube yilapho ukuhlanganiswa kwesampula ngaphansi kwalelo zinga lomthwalo, ukulungiswa okuhambisanayo ngezinkulungwane zemilimitha kuyafundwa kusiqhathanisi futhi kubhalwe kwirekhodi. Ukuhlanganiswa kucatshangwa ukuthi kuzuziwe uma ukukhokhwa kwesampula kungu-Δh ≤0,02 mmokwesikhathi se24ihora. Ngemuva kokuba ukuhlanganiswa kufinyelelwe, izinga elilandelayo lomthwalo lisetshenziswa futhi yonke inqubo iphindaphindiwe ngendlela efanayo nokunye kuze kufike izinga lokugcina lomthwalo.
Ukuhlolwa kokuqiniswa okuvinjelwe ukunwetshwa kwe-lateral kwenziwa ngokulayisha nokulayishwa, ukuze kunqunywe izakhiwo ezinwebekayo zomhlabathi. Ngemva kokulayisha isampula ngezinga elithile, siyethula ngokunensa okufanayo njengoba besiyilayisha. Ukukhulula ngokuvamile kwenziwa ngemva kwalokho2,0kp/cm2,4,0kp/cm2futhi6,0kp/cm2.
Njengomthetho, ukuhlolwa kwenziwa ngesampuli ngaphansi kwamanzi, ebanjwe eshubhu lengilazi elingakwesokunxele endaweni ephakeme yesampula ku-apparatus. Ukuhlola ukucindezelwa kwesampula lapho kukhona amanzi kwenziwa ngenxa yalesi sizathu, ngoba ukuhlolwa kuthatha isikhathi eside futhi isampula yoma ngaleso sikhathi, ngenxa yalokho ukucindezelwa kwesampula kungaba ngaphansi kunokucindezelwa kwangempela kwenhlabathi esimweni somswakama wemvelo. Ukwengeza, umswakama wemvelo wenhlabathi ungase ube ngaphezu kwalokho owawuyikho ngesikhathi sokusampula, ikakhulukazi lapho izinga lamanzi angaphansi komhlaba likhuphuka, okungase kuholele ekuphambukeni okukhulu ekucindezelekeni kwangempela kwenhlabathi phakathi nenkathi yezinga eliphezulu lamanzi.
Imiphumela yokuhlolwa isetshenziswa ezinhlotsheni ezintathu zemidwebo, okuyidayagramu yokucindezelwa okuhlobene, idayagramu yokushintsha i-porosity coefficient kanye nedayagramu yokuxazulula isikhathi.
Umdwebo wokucindezela ohlobene
Lo mdwebo utholakala uma ukucindezela okuvamile kusetshenziswa kusampula ku-abscissa axis σ = P/A, lapho P kuwumthwalo osebenza kusampula ngetshe lesihlungi esingaphezulu ku-kp/cm2, A indawo ehambisana nengxenye ye-abscissa, isampula iyisixhumi esihlobene ne-app. Δh/h lapho Δh iwukuqedwa kwesampula ngaphansi komthwalo Δσ ngesikhathi sokuhlanganiswa, h ubude besampula ngaphambi kokulayisha (fig. 2).
Fig. 2. Umdwebo wokucindezela ohlobene
Ngesikhathi kulayishwa, umdwebo wokucindezelwa okuyinhloko a.
Ngesikhathi sokuthulula, uma ukutholwa kwamanzi okungavinjwanga kunikwe amandla, ukuze isampula lihlale lingaphansi kwamanzi ngesikhathi sokulayishwa, libuyela esimweni salo sangempela, okungukuthi ukuvuvukala. Kodwa-ke, isampula ayibuyeli esimweni sayo sokuqala, okusho ukuthi senziwe i-plastic (unomphela) deformation ngaphezu kokunwebeka. Ngakho-ke, kulokhu, umdwebo wokuvuvukala b utholakala ngesikhathi sokuthulula. Kodwa-ke, uma ukuhlolwa kwenziwe ngaphandle kokuthola amanzi, esikhundleni somdwebo ovuvukalayo, lokho okubizwa ngokuthi diagram of elasticity.
Uma isampuli ilayishwa futhi ngemva kokulayishwa, umdwebo wesibili wokucindezela c uyatholakala. Umdwebo wokuvuvukala kanye nomdwebo wesibili wokucindezela c wakha iluphu ye-hysteresis phakathi kwakho. Ngobumba, izihibe ze-hysteresis zibalulekile ngakho-ke ukuguqulwa endaweni yokuvuvukala nokucindezelwa kwesibili (imidwebo b ne-c) akubhekwa njenge-elastic, kodwa ebuyiselwa emuva, ngoba ayilingani nomthwalo ngokomthetho kaHooke. Ukonakala endaweni yokuminyanisa okuyinhloko (umdwebo a) engxenyeni lapho kungabuyanga khona kungunaphakade (akunakuhlehliswa).
Imojula yokucindezela komhlaba
Kusuka kumdwebo wokuminyanisa okuhlobene, sithola ngokomthetho ka-Hooke ngokufana kuya kumodulus ka-Jung yokunwebeka E kwento enwebekayo, imodulus yokucindezelwa komhlabathi Ms
Ms = Δσ / (Δh/h) [kp/cm2],
lapho Δσ kuwukunyuka komthwalo, Δh/h ukucindezelwa okuhambisanayo okuhambisanayo, okuthathwe kumdwebo oyinhloko wokucindezela a (fig. 2).
Imoduli yokucindezelwa yenhlabathi Ms iyahluka kumodulus yokunwebeka E kwezinto ezinwebekayo, ngenxa yokuthi Ms akahlali njalo kwinto eyodwa kodwa iyashintshashintsha futhi iyanda ngomthwalo ovamile σ. Ngakho-ke, inani elithile elithile lemodulus yokucindezela Ms linganikezwa kuphela isikhawu esisodwa esincane somthwalo ovamile wenhlabathi Δσ. Uma inani lemojuli Ms lingaphezulu, ukucindezelwa kwenhlabathi kuphansi futhi ngokuphambene nalokho. Ngokwemithetho yethu yesisekelo, umbandela olandelayo wemoduli yokucindezelwa komhlabathi esimweni sawo semvelo uyamukelwa:
Ukuhlelwa okungezansi kudluliswa kusuka embhalweni wokuqala, okufaka phakathi isikhawu esiphindiwe 100-400 kp/cm2. Ayihloliwe noma ivunyelaniswe nemithetho yamanje.
Ms = 0 - 20 kp/cm2 inhlabathi ecindezela kakhulu
Ms = 20 - 50 kp/cm2 inhlabathi ecindezela kakhulu
Ms = 50 - 100 kp/cm2 inhlabathi ecindezelayo emaphakathi
Ms = 100 - 400 kp/cm2 inhlabathi ecindezelwa kancane
Ms = 100 - 400 kp/cm2 inhlabathi ecindezelwa kancane
Ms = 400 - 1000 kp/cm2 inhlabathi ecindezelwa kancane
Ms > 1000 kp/cm2 inhlabathi ecindezelwayo ephansi kakhulu.
Imojula yokunwebeka komhlaba
Ngendlela efanayo, sithola imodyuli yokunwebeka kwenhlabathi E:
E = Δσ / (Δh/h) [kp/cm2],
lapho ukuqina kokucindezelwa okuhlobene Δh/h kuthathwa kumdwebo wokunwebeka kwenhlabathi ngokunyuka kokucindezela okuvamile okungu-Δσ.
Umhlabathi ojwayelekile ohlanganiswe futhi oqiniswe ngokweqile
Sl.3. Umdwebo wezinguquko ku-porosity coefficient yesampula yomhlabathi ephazamisekile
Uma senza ukuhlolwa kwe-oedometer ngesampula ephazamisekile, esiyifake ku-apparatus endaweni yokukhiqiza, futhi sihlela imiphumela yokuhlolwa kumdwebo woshintsho ku-porosity coefficient e kuye ngengcindezi σ (Fig.3) ukugeleza kokuhlanganisa kumelelwa imidwebo 1 ngomthwalo oyinhloko, 2 ukuze uthole usizo, 3 ngokulayisha kwesibili kuze kufike kumkhawulo ongu-a wesandiso esiyinhloko somthwalo σa kanye 4 ngaphezu kwalowo mkhawulo.
Umdwebo wokusiza2kanye nomdwebo wesibili wokucindezela3yakha iluphu ye-hysteresis ngemuva komdwebo4iqhubeka esandisweni somdwebo1, ngaphandle kokuphuka, njengokungathi akukho ukuthulula nokulayishwa kabusha.
Sl.4. Umdwebo wokushintsha kwe-porosity coefficient yesampula yomhlabathi engaphazanyiswa
Kodwa-ke, uma senza ukuhlolwa kwe-oedometer ngendlela efanayo nangaphambili ngesampula elingaphazanyiswa elithathwe ekujuleni okuthile komhlabathi (isig.4), umdwebo womthwalo wesibili3izobonisa emthwalweni owodwa othize σb ukuphuka endaweni b, ngemva kwalokho umdwebo uzoqhubeka4abe nomthambeka ophakeme. Lokhu kuphuka kwenzeke ngenxa yokuthi inhlabathi okwathathwa kuyo isampula yayingaphansi komthwalo omkhulu p=γt kunomthwalo wesampula σ ku-oedometer. Umthwalo ophezulu u-p usuka esisindweni sezingqimba zenhlabathi engaphezulu ezikhona uye phezu kwendawo, esikubiza ngokuthi ukucindezela kwenhlabathi, noma emthwalweni wezingqimba zenhlabathi zangaphambili ezithathwe ngokuhamba kwesikhathi ukuguguleka noma emhlabathini we-moraine noma iqhwa, esikubiza ngokuthi ukulayisha kuqala. Ukubonakala kokuqiniswa ngokweqile kuyisici sobumba ikakhulukazi, lapho sihlukanisa phakathi kobumba olujwayelekile oluhlanganisiwe noluqinisiwe.
Ubumba oluhlanganisiwe ngokuvamile
Ngokuvamile ubumba oluhlanganisiwe lusekujuleni okungashoni ngaphansi kwendawo engaphansi, olungakaze luvezwe ngaphambilini ukuze lulayishwe ngaphambili. Isampula yalolu bumba, elayishwe ku-oedometer enemithwalo emikhulu kunesisindo sezendlalelo “zenhlabathi yokucindezela”, ibonisa ukugeleza okuqhubekayo kokuqiniswa, ngaphandle kokuphuka kumdwebo wokucindezela okuhlobene noma kumdwebo wokushintsha kwe-porosity coefficient. Ukuhlaliswa kwalolu bumba ngaphansi komthwalo wento kuvamile, okungukuthi ngaphansi komthwalo othile, ukulungiswa kunciphisa ngokuhamba kwesikhathi.
Ubumba oluhlanganiswe ngokweqile
Ubumba oluqiniswe ngokweqile lusekujuleni okukhulu noma seluke lwalayishwa ngaphambilini. Isampula yalolu bumba olulayishwe ku-oedometer enengcindezi enkulu kunokucindezela kwenhlabathi noma ukulayisha kuqala kubonisa ukuphuka kumdwebo wokucindezela okuhlobene noma kumdwebo wokushintsha i-porosity coefficient, okuthiwa. geological fracture g, noshintsho olunamandla endleleni (Fig.5a). Ukuhlala kwalolu bumba ngaphansi kwesakhiwo kuncane kumthwalo ongaphansi kokucindezela kwenhlabathi noma ukulayisha kuqala σ1, kodwa iba nkulu kakhulu emithwalweni engaphezu kuka-σ1.
Uma ikhefu le-geological lingachazwanga ngokucacile, khona-ke kunqunywa ukusebenzisa ama-tangents kumdwebo (Fig.5b).
Sl.5. Umdwebo wezinguquko ku-porosity coefficient yobumba oluhlanganiswe ngokweqile
Umdwebo wokulungiswa kwesikhathi
Lo mdwebo, obizwa nangokuthi umdwebo wokuhlanganisa, utholakala lapho, ngezinga ngalinye lokulayisha isampula ku-edometer, isikhathi t emahoreni sisetshenziswa ku-abscissa axis, futhi ukulungiswa ngo-mm ku-eksisi edidiyelwe (Fig.6a) noma ku-% yenani eliphelele (Fig.6b).
Sl.6. Umdwebo Wokukhokha Isikhathi
Inhlabathi engaboshiwe futhi eboshiwe iziphatha ngendlela ehlukile ngaphansi komthwalo. Inhlabathi exekethile, njengesihlabathi, inezimbotshana ezinkulu, lapho amanzi ephuma ngokushesha ngaphansi komthwalo, ukuze inhlabathi ihlale ngokushesha, ngokuxazululwa okukhulu okwenzeka ekuqaleni komthwalo futhi kufinyelele ekuxazululeni kokugcina ngomthwalo onikeziwe ngesikhathi esifushane kakhulu. Umhlabathi ohlangene njengobumba unezimbotshana ezincane lapho amanzi okunzima ukukhama khona ngaphansi komthwalo. Kunezigaba ezimbili zenqubo yesikhathi sokuhlala kwenhlabathi ehlangene. Esigabeni sokuqala, ngokushesha ngemva kokufaka umthwalo emhlabathini, njengoba amanzi engakwazi ukugeleza ngaphandle kwama-pores, agxilile futhi athole wonke umthwalo osetshenzisiwe. Esigabeni sesibili, amanzi e-pore agxilile aqala ukuphuma ngaphansi kokucindezeleka kwawo ngenxa yomthwalo, odluliselwa kancane kancane ezinhlayiyeni zenhlabathi eqinile. Kulesi sigaba sesibili, izinhlayiya ziyahlangana futhi ama-pores ayancipha. Inqubo ye-subsidence iyaqhubeka kuze kube yilapho amanzi okucindezela ephoqeleka ngaphandle kwama-pores, okungukuthi kuze kube yilapho isimo esicindezelekile samanzi e-pores siphela. Ngakho-ke, ukuhlanganiswa kwenhlabathi ngokuyinhloko kuyinkinga ye-hydrodynamic, encike ekungeneni kwenhlabathi kanye ne-porosity. Endabeni yobumba, ukuvuthwa kwayo kuphansi, inqubo yokuhlanganisa ingathatha isikhathi eside kakhulu, futhi ngaphezu kwalokho, izindawo zokuhlala zingaba zikhulu kakhulu ngenxa ye-porosity ephakeme kakhulu kunesihlabathi. Ngokwesisekelo sokuhlolwa kokuhlanganiswa, inkambo yesikhathi sokukhokhelana ingabalwa kuso sonke isikhathi sokuhlanganisa futhi ngezigaba ngazinye.