Namuhla, i-Savo Kusić igxile emafasiteleni okhuni, amafasitela okhuni-aluminium, amafasitela ngokwezifiso, umnyango kanye nezicelo zekhotheshini. Lo mbhalo uhlala ungowomlando we-geotechnical futhi awuwona umnikelo wokuhlolwa zelabhorethri, idizayini ye-geotechnical noma i-earthworks.
Kunezindlela ezimbalwa zokunquma izakhi zokumelana nenhlabathi yangaphakathi, ukubumbana kanye ne-engeli yokungqubuzana kwangaphakathi kusetshenziswa izivivinyo zaselabhorethri, phakathi kwazo ukuhlolwa direct shear kanye nokuhlola triaxial compression yizo ezidume kakhulu.
Ukugunda okuqondile
Ukuhlola kwenziwa emshinini osebenza ngesigaba esingunxande sohlobo A. I-Casagrandea noma kumshini oyisiyingi wohlobo lwe-Hvorsleva. Sizochaza ukuhlolwa ngedivayisi yesigaba esingunxande, okuyisona esisetshenziswa kakhulu. Kuzo zombili izimo, ukuhlolwa kwenziwa ngesampula engaphazanyiswa, noma ngesampula ephazamisekile endaweni yokukhiqiza, lapho ukuhlolwa kunenani lokuqhathanisa.
Izinsiza zokugunda okuqondile kwesigaba esingunxande (fig. 1)
Fig. 1_Cross section ye-Casagrande’s direct shear apparatus_
Idivayisi iqukethe izingxenye ezimbili, uhlaka olungaphezulu nolungaphansi, lapho oluphansi lumile, kuyilapho olungaphezulu lunyakazeka futhi lungahanjiswa kwelaphansi ngaphansi kwethonya lamandla avundlile Z, asebenza endizeni yokuthintana yohlaka olungaphezulu noluphansi.
Isampula yenhlabathi ifakwa endandeni yensimbi engunxande, ngokuvamile engusayizi 100 × 100 × 30 mm, noma lezo zilinganiso lapho ziklwejwa kahle. Amatshe okuhlunga abekwe ngaphezulu nangaphansi kwesampula, bese yonke into ifakwa eringini ye-apparatus, ebese igcwaliswa ngamanzi. Idivayisi yokulayisha okuqondile ibekwe kusampula. Itshe lokuhlunga elingaphezulu lixhunywe ohlelweni lokulayisha okuma mpo kwesampula, kuyilapho eliphansi lixhunywe eziteshini zamanzi, lapho isampula ingagcinwa esimweni sokugcwala phakathi nokuhlolwa, ukuze kukhishwe ukuhlangana okubonakalayo.
Ukuze ungabandakanyi ukungqubuzana endaweni yokuxhumana phakathi kozimele ongaphezulu nophansi, kukhona amadivayisi anohlaka olungaphezulu olusontekile, lapho uhlaka olungaphezulu lunyakaza ngaphansi komthelela wamandla okugunda ovundlile. Ngaphezu kwalokho, izindawo zokuthintana zefreyimu engaphezulu nephansi zimbozwe nge-petroleum jelly. Esinye isifanisi 2 sokubhalisa ukonakala okuqondile nokuvundlile kufakiwe kudivayisi.
Ukwenza izivivinyo zokugunda okuqondile
Zikhona kakhulu2izinhlobo zokuhlolwa okuqondile kwe-shear: fast kanye slow test. Ukuhlola okusheshayo kuhlanganisa ukulayisha isampula ngomfutho othize oqondile, ovame ukuba ngu-0,50;1,0;2,0;3,0futhi4,0kp/cm2, linda ukuhlanganiswa, okucatshangwa ukuthi kufinyelelwe uma ukuncipha ngesikhathi24amahora Δh ≤0,02 mm, bese kusetshenziswa amandla okugunda avundlile Z, obukhulu, asetshenziswa1/20noma1/40ingxenye yamandla aqondile P, akhuphuka njalo ngeminithi ngenani elifanayo kuze kube yilapho kuphuka inhlabathi. Ngesikhathi sokusetshenziswa kwamandla okugunda okuvundlile, ukuhamba kohlaka olungaphezulu kuhlale kuqashwe ngokufunda kusiqhathanisi futhi ukuguqulwa okuvundlile kubhalwe kulogi ngokushesha ngaphambi komthwalo omusha ngamunye. Isikhathi, lapho isiqhathanisi sibonisa ukunyakaza okungazelelwe, sithathwa njengokuphulwa komhlabathi.
Ukuhlolwa okusheshayo kusetshenziselwa inhlabathi enobumba, ukuhlanganiswa kwayo kwemvelo ngaphansi komthwalo omusha kuhamba kancane futhi kuhambisana nale ndlela yokwenza ukuhlolwa.
Slow kwenziwa ngendlela efanayo nangaphambili ngomehluko owodwa kuphela wokuthi amandla okugunda okuvundlile akhuphuka esikhathini eside, okungaba 2, 5 kanye 15 mamaminithi noma kuze kube yilapho ukuhlanganisa, okusho ukunganaki ngokuphelele kuze kube umugqa ovundlile. Inkambo yokuhlanganisa ngaphansi komthelela wamandla avundlile igadwa kusiqhathanisi 9 (fig. 1).
Ukuhlola okunensayo kusetshenziswa enhlabathini enesihlabathi noma enothuli, lapho esimweni sokwanda kwamandla okugunda okuvundlile ngesikhathi esifushane, ukugunda kwesampula ku-apparatus kuzosheshisa ngenxa yomphumela wamanzi agcizelelwe ezimbotsheni, ezingeke zihambisane nenqubo yemvelo. Ngakho-ke, isikhathi sokuphumula siyakhula ngokucoleka kwezinhlayiya zenhlabathi ezingaboshiwe, ukuze sikwazi ukulinganisa ukucindezela kwamanzi ezimbotsheni zenhlabathi nengcindezi yamanzi yangaphandle. Lokhu kulinganisa kufinyelelwa ngokushiya isikhathi esanele ngaphansi komphumela wezinga ngalinye lomthwalo ovundlile, ukuze amanzi adlulele ezimbotsheni akhanywe ngetshe lokuhlunga.
Ngaphezu kwezivivinyo ezishiwo, kwezinye izimo ukuhlolwa okusheshayo ngaphandle kokuhlanganiswa ngaphansi komthwalo oqondile kuyenziwa, okungukuthi amandla okugunda avundlile asetshenziswa ngokushesha ngemva kokwethula isampula ku-apparatus nokuyilayisha ngomthwalo oqondile. Kodwa-ke, le ndlela yokukhipha isetshenziswa ngaphansi kwezimo ezikhethekile, njengendawo yothango olusanda kufakwa olwenziwe ngenhlabathi yobumba, olulayishwa ngokushesha ngemva kodonga ngaphandle kokuminyanisa ngaphambili.
Ukunqunywa kwe-engeli yokungqubuzana kwangaphakathi nokuhlangana
Ngokusekelwe emiphumeleni yokuhlolwa, i-shear stress
τ=Z/A ku-kp/cm²,
etholakala kumandla okugunda Z ku-kp ngesikhathi sokwehluleka kanye nendawo enqamula ingxenye yesampula A ku-cm². Ukuhlola kwenziwa nge-3 kuya ku-4 amathuluzi alayishwe ngokucindezela okuvamile okuhlukile σ=P/A ku-kp/cm² lapho P kuwumthwalo oqondile wesampula ku-kp. Amanani alandelayo okucindezela okuvamile avame ukuthathwa: 1,0; 2,0; 3,0 kanye nokuthi 4,0 kp/cm².
Fig. 2. Umdwebo wokukhubazeka okuvundlile
Ngokusekelwe kumdwebo wezinto zangaphakathi zokungqubuzana, izinhlobo ezimbili zemidwebo 1 kanye nomdwebo wokukhubazeka okuvundlile (ifig. 2) ziyatholakala.
Umdwebo wokuguga okuvundlile utholwa ngokusebenzisa ukugudluka okuvundlile ΔL nge-mm yohlaka olungaphezulu lwedivayisi kuya kophansi ku-eksisi ye-abscissa, etholwa ngokufunda isiqhathanisi 9, kanye naku-eksisi ehambisanayo _τ_cm shear ehambisanayo. 2).
Kuya ngokucinana kwenhlabathi, umdwebo 1 wokucindezelwa kanye nomdwebo 2 wempahla exegayo uyatholakala.
Okokusebenza okuhlangene, ingcindezi ye-shear τ inyuka ekuqaleni ngokucijile ngokuhlobene nokugudluka okuvundlile ΔL ifike emkhawulweni we-proportionality P, bese ihamba kancane, kuyilapho ijika lomdwebo.1inyuka futhi ifinyelele ekuphakameni okuphezulu B, ngemva kwalokho umdwebo wehla ngobude obuthile, ukuze ekugcineni ufinyelele ukugeleza okuvundlile. Indawo yokukhuphuka komugqa oqondile womdwebo ovundlile wokuguquguquka, lapho ukwanda kokucindezelwa kwe-shear kuhambisana nokwanda kokuguquguquka, kucatshangwa ukuthi yindawo yokuguqulwa kwe-elastic. Ngalé komkhawulo P, ukwanda kokucindezelwa kokugunda kwehla ngokuya ngokwanda kokonakala ΔL kuze kufike endaweni ephakeme kakhulu B yomdwebo. Kule ndawo, impahla iqala “ukugeleza” futhi yamukelwa njengendawo yokuguqulwa kwepulasitiki. Iphuzu eliphakeme kakhulu lomdwebo B1imelela ukucindezeleka okukhulu kwe-shear max τ, futhi kucatshangwa ukuthi ukuphuka kwenhlabathi kwenzeka kuleli phuzu, okungukuthi lelo phuzu B liyindawo yokuphuka. Ngaphandle kwephuzu B, impahla isesimweni se-liquid, amandla e-shear ayancipha, futhi kucatshangwa ukuthi kule ndawo, lapho ukuxhumana phakathi kwezinhlayiya kuphukile, kukhona ukumelana nokuslayida kuphela okuphikisana namandla okugunda okuvundlile. Khomba G lapho umdwebo1idlula iqonde evundlile yamukelwa njengomkhawulo wokuslayida.
Ingcindezi yokugunda emkhawulweni wokuhluleka B ibizwa ngokuthi amandla okugunda noma amandla okugunda ahlanzekile τf, kuyilapho ukucindezelwa kokugunda emkhawulweni wokukhipha G kubizwa ngokuthi amandla okushelela τg.
Okokusebenza okuxekethile, umdwebo wokugudluka ovundlile nawo unesifunda esinwebekayo esinomkhawulo wokulinganisa P, kodwa phansi komfula kuyisifunda sepulasitiki esifika kumkhawulo wokushelela ongu-G, okungukuthi umkhawulo wokucindezelwa kokugunda ulingana namandla omkhawulo, ukushelela (τ=τg), ngale kwalokho uketshezi lwento.
Sl.3. Umdwebo wokugunda, a) wenhlabathi ehlangene, b) wenhlabathi engahlangani
Umdwebo we-shear utholakala lapho ingcindezi evamile σ ku-kp/cm isetshenziswa ku-abscissa axis.2, kanye ne-axis ehambisanayo amandla okugunda ahambisanayo τf ku-kp/cm2, lapho womabili la manani asetshenziswa esikalini esifanayo (I-Fig.3). Njengoba amandla okugunda τf enhlabathi enyuka ngomfutho ojwayelekile σ, kuzoba nezingcindezi ezihlukene σ1 thola amaphuzu A, B, C, kanye no-D, amele amandla okugunda ahambisanayo.
Ukuthola amaphuzu ngamanye A, B, C kanye no-D emdwebeni3ngenhlabathi ehlangene (isib.3a), amandla okuslayida _τ_g ayamukelwa. Kodwa-ke, endabeni yenhlabathi enobumba, izinto ziqala ukugeleza isikhathi eside ngaphambi kokuba kufinyelelwe umkhawulo wokushelela G, futhi kukhona ukuthambekela kokuthatha amandla okugunda emkhawulweni we-proportionality P ukuze kunqunywe ukuhlangana c kanye ne-angle yokungqubuzana kwangaphakathi kwenhlabathi, kodwa njengoba kuncane kakhulu, amandla e-shear lapho i-deformation ΔL ivame ukwamukela umdwebo.2okuphindwe kabili kunokonakala esigabeni sangaphambilini sokulayisha ku-apparatus. Lawa mandla asendaweni ethile phakathi komngcele ka-P no-B, okungukuthi, u-G (fig.2).
Amaphoyinti okuxhuma A, B, C kanye no-D kumdwebo 76a unikeza umdwebo wokugunda, okuwumugqa oqondile ezivivinyweni eziyimpumelelo. Ngokunweba idayagramu empambanweni yomgwaqo nge-eksisi edidiyelwe, kokuthi σ = 0, itholwa ngokususelwe kuphethini ye-Coulomb τf = c+σ tgϕ ukuthi τf = c = ukuhlangana kwenhlabathi, kuyilapho ukuthambeka komdwebo oqonde ku-engeli evundlile kunikeza i-engeli evundlile. Ngokunweba umdwebo wokugunda ngakolunye uhlangothi lwe-eksisi edidiyelwe, ingcindezi ngenxa yokuhlangana pk itholakala eksisi ye-abscissa, lapho ubukhulu bokuhlangana c buvezwa njengokulingana nokumelana nokungqubuzana:
c = pk tgϕ, isukaphi pk = c/tgϕ
Ngokwenhlabathi engahlangani, njengesihlabathi, umdwebo wekhiwane. 3b, edlula kumsuka wokuxhumanisa, njengoba kokuthi σ = 0 sithola τ = 0. Nokho, uma isihlabathi sinohlamvu oluhle futhi simanzi, umdwebo ofana nalowo osekhiwaneni. 3a, ngokuhlangana okuncane c, okubonisa ukuhlangana okubonakalayo. Kuleso simo, ingcindezi pk ku-eksisi ye-abscissa enwetshiwe ngakolunye uhlangothi lomsuka wokuxhumanisa imelela ingcindezi ye-capillary.
Kufanele kuqashelwe ukuthi ukunqunywa kokubumbana kwenhlabathi kanye nokungqubuzana ngokuhlolwa okuqondile kwe-shear kunezinkinga ezimbalwa, okubaluleke kakhulu ukuthi ukwehluleka kwenhlabathi kwenzeka endaweni enqunywe kusengaphambili yokugunda futhi hhayi ebusweni bokumelana okuncane kokugunda, ukuthi ngesikhathi sokugunda kwesampula ku-apparatus, indawo yokugunda iyancishiswa ngenxa yalokho ukunyakaza okuphansi kohlaka olulodwa. ukugunda kungagadwa kuphela ngobude obufushane, ukuze ukumelana nokushelela ngaphezu komkhawulo kungakwazi ukulawula ukuphuka ngokwesilinganiso esanele, ikakhulukazi esimweni senhlabathi ethambile lapho ukuguga kukhulu ngesikhathi sokugunda, njll.
Ukuhlolwa kokucindezelwa kwe-Triaxial
Ukuhlolwa kwenziwa kumshini we-triaxial, onezakhiwo ezihlukile, kodwa zonke zisekelwe kumgomo ofanayo, olandelayo. Isampula engaphazamiseki ngendlela ye-roller ibekwe ngokuqondile endaweni yokuma futhi ivezwe ekucindezelweni kwe-lateral kwesisindo se-liquid kusuka kuzo zonke izinhlangothi bese kuya ekucindezelweni okuqondile, okukhuphuka kancane kancane, kuze kube yilapho ukuphuka kwesampula kubangelwa ebusweni bokumelana okuncane kwe-shear. Ngokusekelwe emandleni okugunda ngesikhathi sekhefu, ukuhlangana kanye ne-engeli yokungqubuzana kwangaphakathi kwenhlabathi kuyabalwa.
Incazelo yedivayisi ye-triaxial
Fig. 4. I-Triaxial apparatus
I-triaxial apparatus (fig. 4) iqukethe ingxenye engezansi ye-base plate yegumbi, lapho kubekwe khona isampula, kanye nasenhla yepiston ukuze kulayishwe isampula eqondile kanye nepuleti elingaphezulu elivala igumbi. Izilinganiso ezivame kakhulu zesampula wudayamitha ϕ=36 mm, ubude h=2,2-2,5_ϕ_. Ububanzi begumbi ngu-D=135mm, ubude H = 180 mm. Ishubhu elincane elingu-K1 lokudonsa isampula kusuka phansi liqala phakathi nendawo yesampula yesitendi, elithola amanzi kusampula ngepuleti elinezimbotshana bese liwakhiphela ngaphandle kwegumbi liwafake eshubhuni yengilazi emile C1. Uma ukuhlolwa kwenziwa ngaphandle kokukhipha isampula, lesi siteshi sisebenza ukukala ukucindezela kwamanzi ezimbotsheni. Esisekelweni sethusi segumbi kukhona isiteshi esingu-K2 sokunikezwa kwesisindo soketshezi ukuze kugcwaliswe igumbi futhi kuzuzwe ukucindezela kwecala ekamelweni kusampula.
Ngepuleti elingaphezulu legumbi kudlula isibambo sepiston ukuze kulayishwe isampula. Isampula ekamelweni lizungezwe ulwelwesi lwerabha, olunwetshwa emikhawulweni yomibili futhi luxhunywe ku-piston kanye nesisekelo ngokusebenzisa izindandatho zenjoloba. Maphakathi nepiston kunesiteshi esingu-K3 sokudonsa isampula ohlangothini olungaphezulu.
Izinhlangothi zegumbi zivalwe ngokwe-hermetically ngesilinda se-Plexiglas egxilwe kumapuleti angaphezulu nangaphansi egumbi ngokusebenzisa izindandatho zenjoloba.
Igumbi libekwe phezu kwesisekelo esiqinile. Ukulayishwa okuvamile kwesampula kwenziwa nge-lever enesisindo, isilinganiso sayo esivame kakhulu ukuthi 1: 10. Uhlelo lokuthola ukucindezela kwe-lateral kusampula egumbini liqukethe ibhodlela elinesisindo soketshezi B, elingeniswa ekamelweni ngeshubhu, i-manometer yokulinganisa ukucindezela komoya kanye nebhodlela elinomoya ocindezelwe. Isiqhathanisi sibekwe ngenhla kwepiston ukuze kulayishwe isampula ukuze kukalwe ukuqedwa kwesampula ngaphansi komthwalo.
Ingcindezi yangemuva yesisindo soketshezi ekamelweni ingalungiswa ngokuthanda kwayo kusetshenziswa ukucindezela komoya ebhodleleni B, ngamavalvu V1 kanye ne-V2. Lokhu kucindezela kubangela ukucindezelwa okuvundlile kusampula σ2 kanye nokuthi σ3, okuthi ngenxa yesigaba esiyindilinga sesampuli alingane σ2 = σ3.
Inqwaba yoketshezi ingaba amanzi acwengekile noma uwoyela, ancanyelwayo ukuze kuvalwe kangcono, ngoba amanzi angadlula ezikulufini. Ngaphansi kwethonya lomfutho womoya ebhodleleni B, inqwaba yoketshezi igcwalisa igumbi kuze kufike ku-valve V6, bese ivala. Umthwalo oqondile wesampula P, odluliselwa cishe ngokungaguquki kusampula ngesibambo se-piston, ehlukaniswa ngendawo ewela ingxenye yesampula A inikeza ukucindezelwa okuma mpo σ1 = P/A
Ukwenza ukuhlolwa kokucindezela kwe-triaxial
Kusampula yokuhlola, icutshungulwa kumshini ohlukile, ukuze i-rola enobubanzi obungu-36 mm, ubude obungu-78 mm noma 90 mm itholwe, lapho kubekwa khona amatshe okuhlunga ukusuka phezulu nangaphansi futhi kufakwe ulwelwesi lwerabha. Khona-ke isampula kanye namatshe okuhlunga kufakwa endaweni yokumisa ekamelweni, imikhawulo, i-membrane yenjoloba idonswa phezu kwe-stand kanye ne-piston yokulayisha futhi ivikelwe ngamasongo enjoloba. Ngokomkhuba wamalabhorethri athile, njengoProf. Skempton eLondon, ukukhipha isampula ekamelweni ngesikhathi sokuhlolwa kusheshiswa ngokuhlanganisa izinhlangothi zesampula ngephepha lokuhlunga, elibekwa ngaphambi kokuthi kudonswe ulwelwesi lwenjoloba. Lapho isampula yethulwa ku-apparatus futhi isilinda se-Plexiglas sigxilile kumapuleti aphezulu naphansi, kungenzeka ukwenza izivivinyo, ezingenziwa ngezindlela ezimbalwa, njengalezi ezilandelayo:
-
Ukuhlolwa okungavulwanga amanzi. Kulezi zivivinyo, ukukhipha isampula akuvunyelwe ngesikhathi sokusetshenziswa kokuhlolwa okuhlangene nokuma mpo, kuyilapho ama-valve V4 kanye ne-V5 evaliwe.
-
Ukuhlola okungagonyiwe ngokuhlanganisa. Ngesikhathi sokusetshenziswa kwengcindezi ye-lateral, isampula iyakhishwa (ama-valve V4 kanye ne-V5 avuliwe), kuyilapho ngesikhathi sokusetshenziswa kwengcindezi eqondile, ukudonsa amanzi akuvunyelwe (V4 kanye ne-V5 ivaliwe).
3_) Amasampula akhishiwe_. Isampula ikhishwa kuso sonke isikhathi sokuhlolwa (amavalvu V4 kanye ne-V5 avuliwe), ukuze ukuhlanganiswa okuphelele kwenzeke futhi kungabikho manzi agcizelelwe adalekayo ezimbotsheni ngesikhathi sokusetshenziswa kwengcindezi eqondile σ1. Lokhu kuhlola kuthatha isikhathi eside, ikakhulukazi ngenhlabathi engangeneki kahle, ngoba ukulayisha okuqondile σ1 kufanele kwenziwe ngenani elikhulu lezigaba ezincane futhi ukuhlanganiswa kufanele kulindwe esigabeni ngasinye. Ngaphezu kwalokho, ukuhlola okukhulunywe ngakho kungenziwa ngamasampuli agcwele kanye agcwele kancane._
Ngokubuka kwamathuba ashiwo ngenhla, ukuhlolwa kokucindezela kwe-triaxial kungenziwa ngezindlela ezihlukahlukene futhi kulungiswe ngokuya ngohlobo lwenhlabathi ngaphansi kwezimo zomthwalo.
Amadivayisi, izinqubo, amayunithi, amanani namaphethini achaziwe adluliswa esuka kumthombo womlando. Umbhalo awulona ucwaningo lwe-geotechnical, iphrothokholi yaselabhorethri, iphrojekthi yesisekelo, ubufakazi bokuqina kwemithambeka noma uhlelo lokumba. Ukukhethwa kwesampula kanye nendlela yokuhlola, isimo sokugeleza kwamanzi kanye nokuhlanganiswa, amanzi angaphansi komhlaba, isimiso sokulayishwa, imithelela yokuzamazama komhlaba kanye nokuphepha kokumba kufanele kunqunyelwe inhlabathi ethile nesakhiwo, ngokuvumelana nemithetho yamanje, nelabhorethri efanelekile kanye nochwepheshe be-geotechnical ogunyaziwe.