Kutsimikiza kwa mgwirizano ndi mbali ya kukangana kwamkati

Masiku ano, Savo Kusić amayang’ana kwambiri mazenera amatabwa, mazenera a matabwa a aluminiyamu, mazenera amwambo, khomo ndi zopempha za mawu. Zolembazi zimakhalabe ngati zakale za geotechnical ndipo sizopereka kuyesa kwa labotale, kapangidwe ka geotechnical kapena Earthworks.

Pali njira zingapo zodziwira zinthu za kukana kwa nthaka yamkati, mgwirizano ndi ngodya ya kukangana kwamkati pogwiritsa ntchito mayesero a labotale, pakati pawo direct shear test ndi triaxial compression test ndizodziwika kwambiri.

Direct shear mayeso

Kuyesaku kumachitika pazida zomwe zili ndi gawo lamakona anayi amtundu wa A. Casagrandea kapena pazida zozungulira zamtundu wa Hvorsleva. Tidzafotokozera kuyesera ndi chipangizo cha gawo lamakona anayi, chomwe chimagwiritsidwa ntchito kwambiri. Pazochitika zonsezi, mayeserowa amachitidwa ndi chitsanzo chosasokonezeka, kapena ndi chitsanzo chosokonezeka pa malo okolola, pomwe mayeserowa ali ndi mtengo wofananira.

Zida zometa mwachindunji gawo lamakona anayi (mkuyu.1)

Mkuyu. 1_Cross gawo la zida zometa ubweya wa Casagrande_

Chidachi chimakhala ndi magawo awiri, chimango cham’mwamba ndi chapansi, pomwe cham’munsi chimakhala chokhazikika, pomwe chapamwamba chimakhala chosunthika ndipo chimatha kusuntha cham’munsi motengera mphamvu yopingasa Z, yomwe imagwira ntchito yolumikizana ndi chimango chapamwamba ndi chapansi.

Zitsanzo za nthaka zimayikidwa mu mphete yachitsulo yamakona anayi, nthawi zambiri kukula kwake 100 × 100 × 30 mm, kapena miyesoyo ikakulungidwa molondola. Miyala yosefera imayikidwa pamwamba ndi pansi pa chitsanzo, ndiyeno zonse zimayikidwa mu mphete ya zida, zomwe zimadzazidwa ndi madzi. Chipangizo chotsitsa choyima chimayikidwa pa chitsanzo. Mwala wapamwamba wa fyuluta umagwirizanitsidwa ndi dongosolo la kukweza kwachitsanzo, pamene lapansi limagwirizanitsidwa ndi njira zamadzi, pogwiritsa ntchito chitsanzocho chikhoza kusungidwa m’malo odzaza panthawi yoyesedwa, kuti asawononge mgwirizano woonekera.

Kuti musakhale ndi mikangano pamalo olumikizirana pakati pa chimango chapamwamba ndi chakumunsi, pali zida zopindika, zomwe chimango cham’mwamba chimasuntha chifukwa cha mphamvu yometa. Kuphatikiza apo, mawonekedwe olumikizana ndi chapamwamba ndi pansi amakutidwa ndi mafuta odzola. Chofananitsa china 2 polembetsa zopindika zoyima ndi zopingasa zikuphatikizidwa mu chipangizochi.

Kuyesa kumeta ubweya mwachindunji

Pali zambiri2mitundu ya mayeso ometa ubweya molunjika: fast ndi slow test. Mayeso a quick amakhala ndi kutsitsa sampuli ndi kuthamanga kwina koyima, komwe nthawi zambiri kumakhala0,50;1,0;2,0;3,0ndi4,0kp/cm2, dikirani kuphatikizika, komwe kumaganiziridwa kuti kukwaniritsidwa ngati kutsika kwapakati pa nthawi ya24maola Δh ≤0,02 mm, ndiyeno mphamvu yometa ubweya yopingasa Z, ya ukulu, imayikidwa1/20kapena1/40gawo la mphamvu yoyimirira P, yomwe imachulukitsa mphindi iliyonse ndi mtengo womwewo mpaka nthaka itasweka. Panthawi yogwiritsira ntchito mphamvu yometa yopingasa, kayendetsedwe ka kayendedwe kapamwamba kamayang’aniridwa nthawi zonse powerenga pa comparator ndipo zopingasa zopingasa zimalembedwa mu chipika nthawi yomweyo musanayambe katundu watsopano. Mphindi, yomwe wofananitsayo akuwonetsa kusuntha kwadzidzidzi, amatengedwa ngati kuswa pansi.

Kuyesedwa kofulumira kumagwiritsidwa ntchito ku dothi ladongo, lomwe kuphatikizika kwake kwachilengedwe pansi pa katundu watsopano kumachedwa ndipo kumagwirizana ndi njira iyi yochitira mayeso.

Slow amachitidwa mofanana ndi kale ndi kusiyana kokha komwe mphamvu yopingasa yometa ubweya imawonjezeka pakapita nthawi yayitali, yomwe ingakhale 2, 5 ndi 15 mmphindi kapena mpaka kugwirizanitsa, kutanthauza kusazindikira kwathunthu mpaka kusakhazikika. Njira yophatikizira pansi pa mphamvu yopingasa imayang’aniridwa pa wofananira 9 (mkuyu 1).

Kuyesa kwapang’onopang’ono kumagwiritsidwa ntchito ku dothi lamchenga kapena lafumbi, pomwe pakuwonjezeka kwa mphamvu yometa ubweya wopingasa pakanthawi kochepa, kumeta kwachitsanzo m’zidazo kumathamanga chifukwa cha mphamvu ya madzi opanikizika mu pores, zomwe sizingafanane ndi zochitika zachilengedwe. Choncho, nthawi imeneyi ukuwonjezeka ndi fineness wa unbound nthaka particles, kuti athe equalization wa kuthamanga madzi mu nthaka pores ndi kunja madzi kuthamanga. Kulinganiza kumeneku kumatheka posiya nthawi yokwanira pansi pa mphamvu ya mulingo uliwonse wa katundu wopingasa, kotero kuti madzi ochulukirapo mu pores amatsitsidwa kudzera pamwala wosefera.

Kuphatikiza pa mayesero otchulidwawo, nthawi zina kuyesa mwamsanga popanda kuphatikizika pansi pa katundu woyima kumachitidwa, mwachitsanzo, mphamvu yopingasa yometa ubweya imayikidwa mwamsanga mutangoyambitsa chitsanzo mu chipangizo ndikuchiyika ndi katundu woyima. Komabe, njira yophera imeneyi imagwiritsidwa ntchito pamikhalidwe yapadera, monga ngati mpanda wongoikidwa kumene ndi dothi ladothi, womwe umakwezedwa ukangokhomera popanda kuphatikizika.

Kutsimikiza kwa mbali ya kukangana kwamkati ndi mgwirizano

Kutengera zotsatira za mayeso, kumeta ubweya wa ubweya

τ=Z/A mu kp/cm²,

zomwe zimachokera ku mphamvu yometa ubweya Z mu kp panthawi ya kulephera komanso gawo laling’ono la chitsanzo A mu cm². Zochitika zimachitika ndi3ku4zida zodzaza ndi kukakamiza kosiyana kosiyana σ=P/A mu kp/cm² kumene P ndi katundu woyima wa chitsanzo mu kp. Makhalidwe otsatirawa azovuta zanthawi zonse amatengedwa:1,0;2,0;3,0ndi4,0kp/cm².

Sl.2. Chiwonetsero cha zopindika zopingasa

Kutengera ndi chithunzi cha zinthu zokangana zamkati, mitundu iwiri yazithunzi imapezedwa1ndi chithunzi cha deformations yopingasa (mkuyu.2).

Chithunzi cha zopingasa zopingasa zimapezedwa pogwiritsa ntchito kusamutsidwa kopingasa ΔL mu mm wa chimango chapamwamba cha zida kupita kumunsi pa abscissa axis, yomwe imapezeka powerenga comparator.9, ndi pa axis yolumikizira kumeta ubweya kofananirako τ mu kp/cm² (Chith.2).

Kutengera kuphatikizika kwa dothi, chojambula chimapezeka1za compact ndi chithunzi2kwa zinthu zotayirira.

Pazinthu zophatikizika, kumeta ubweya wa ubweya τ kumawonjezeka poyamba kwambiri poyerekeza ndi kusamutsidwa kopingasa ΔL mpaka malire a proportionality P, kenako pang’onopang’ono, pamene mphira wa chithunzicho.1kumawonjezeka ndi kufika pazipita kutalika B, kenako chithunzi amachepetsa kwa utali wina, kuti potsiriza kufika yopingasa otaya. Dera la kukwera kwa mzere wowongoka wa chithunzi chopingasa chopingasa, momwe kuwonjezereka kwa kumeta ubweya kumayenderana ndi kuchuluka kwa mapindikidwe, kumaganiziridwa kuti ndi gawo la elasticity. Kupitilira malire P, kuwonjezereka kwa kumeta ubweya kumachepa malinga ndi kuchuluka kwa zopindika ΔL mpaka pamwamba pa B pazithunzizo. M’dera lino, zinthu zimayamba “kuyenda” ndipo zimatengedwa ngati malo a pulasitiki. Malo apamwamba kwambiri pazithunzi za B1imayimira kupanikizika kwakukulu kwa shear max τ, ndipo zimaganiziridwa kuti kusweka kwa nthaka kumachitika panthawiyi, kutanthauza kuti mfundoyo B ndiyo yosweka. Kupitilira mfundo B, zinthuzo zili mumadzimadzi, mphamvu yakumeta ubweya imachepa, ndipo zimaganiziridwa kuti m’dera lino, pomwe kugwirizana pakati pa tinthu tating’onoting’ono kumasweka, pali kukana kokha komwe kumatsutsana ndi mphamvu yakumeta ubweya yopingasa. Lozani G pomwe chithunzicho1akudutsa mu njira yopingasa amatengedwa ngati kutsetsereka malire.

Kumeta ubweya pa malire olephera B kumatchedwa mphamvu yakumeta ubweya kapena kumeta ubweya wonyezimira τf, pamene kumeta ubweya pa malire a zokolola G kumatchedwa slip mphamvu τg.

Kwa zinthu zotayirira, chopingasa kusamutsidwa chithunzi alinso ndi dera zotanuka ndi proportionality malire P, koma kunsi kwa mtsinje ndi pulasitiki dera mpaka kutsetsereka malire G, i.e. pazipita kukameta ubweya kupsyinjika ndi wofanana ndi malire mphamvu, kuzembera (τ=τg), kupyola kumene madzi mkhalidwe wa zinthu.

Sl.3. Kumeta ubweya wa dothi, a) kwa dothi lolumikizana, b) kwa dothi losagwirizana

Chithunzi cha kukameta ubweya chimapezeka pamene kuthamanga kwabwino σ mu kp/cm kumayikidwa pa abscissa axis.2, ndi pa axis yolumikizana mphamvu yometa ubweya yofananira τf mu kp/cm2, pomwe zonse ziwirizi zimagwiritsidwa ntchito pamlingo womwewo (Mkuyu.3). Popeza mphamvu yakumeta ubweya wa nthaka imachulukitsidwa ndi kukakamiza kwanthawi zonse σ, kudzakhala pazovuta zosiyanasiyana σ1 pezani mfundo A, B, C, ndi D, zomwe zikuyimira mphamvu zometa ubweya zofananira.

Kuti mupeze mfundo zaumwini A, B, C ndi D pa chithunzicho3kwa dothi logwirizana (mkuyu.3a), mphamvu yotsetsereka _τ_g imatengedwa. Komabe, pankhani ya dothi ladongo, zinthuzo zimayamba kuyenda nthawi yayitali isanafike malire otsetsereka G, ndipo pali chizolowezi chotengera kumeta ubweya wa mphamvu pamalire a proportionality P kuti adziwe kugwirizana c ndi mbali ya kukangana kwamkati kwa nthaka, koma popeza ndi yaying’ono, mphamvu yakumeta ubweya yomwe mapindikidwe ΔL nthawi zambiri amatengera chithunzicho.2kawiri kuposa mapindikidwe pa siteji yapita ya Mumakonda mu zida. Mphamvu iyi ili penapake pakati pa malire a P ndi B, ndiko kuti, G (mkuyu.2).

Kulumikiza mfundo A, B, C ndi D pa chithunzi 76a imapereka chithunzi cha shear, chomwe ndi mzere wowongoka pamayeso opambana. Pakukulitsa chithunzicho pamphambano ndi axis yolumikizira, ya σ = 0, imapezedwa kutengera mtundu wa Coulomb τf = c+σ tgϕ kuti τf = c = kulumikizana kwa dothi, pomwe otsetsereka kwa chithunzicho kulowera kopingasa mkati kumapereka ngodya. Mwa kukulitsa chithunzi cha kukameta ubweya kumbali ina ya axis yogwirizanitsa, kupsinjika chifukwa cha mgwirizano pk kumapezeka pa abscissa axis, pamene kukula kwa mgwirizano c kumasonyezedwa ngati kofanana ndi kukana kukaniza:

c = pk tgϕ, kuchokera kuti pk = c/tgϕ

Pa dothi losagwirizana, monga mchenga, chithunzi cha mkuyu. 3b, yomwe imadutsa poyambira, popeza σ = 0 timapeza τ = 0. Komabe, ngati mchenga uli wonyowa bwino komanso wonyowa, chithunzi chofanana ndi cha mkuyu. 3a, yokhala ndi mgwirizano wocheperako c, womwe umayimira mgwirizano wowoneka bwino. Zikatero, kupsyinjika pk pamtunda wotalikirapo wa abscissa kumbali ina ya chiyambi chogwirizanitsa kumayimira kupsinjika kwa capillary.

Kuyenera kuzindikirika kuti kutsimikiza kwa mgwirizano wa nthaka ndi kukangana ndi kuyesa kwachindunji kumeta ubweya kumakhala ndi zovuta zingapo, zofunika kwambiri zomwe zimakhala kuti kulephera kwa nthaka kumachitika pamtunda wokonzedweratu osati pamwamba pa kumeta ubweya wonyezimira, kuti pakumeta ubweya wa chitsanzo mu chipangizocho, kumeta ubweya wa ubweya kumachepetsedwa chifukwa cha kusuntha kwachitsanzo panthawi ya kusuntha kwachitsulo. kumeta ubweya kumangoyang’aniridwa pautali wochepa, kotero kuti kukana kutsetsereka kupitirira malire sikungathe kuwongolera kusweka mokwanira, makamaka pa nthaka yofewa pamene zopindika panthawi yometa ndi zazikulu, ndi zina zotero.

Triaxial compression test

Mayeserowa amachitidwa pa zida za triaxial, zomwe zimakhala ndi mapangidwe osiyanasiyana, koma zonse zimachokera ku mfundo yomweyi, yomwe ili motere. Chitsanzo chosasokonezeka mu mawonekedwe a wodzigudubuza amayikidwa vertically pa choyimilira ndi poyera kuti ofananira nawo kuthamanga kwa madzi misa kuchokera kumbali zonse ndiyeno kukakamiza ofukula, amene pang’onopang’ono kuwonjezeka, mpaka fracture ya chitsanzo chifukwa pamwamba pa kukana kukameta ubweya pang’ono. Kutengera mphamvu ya kukameta ubweya pa nthawi yopuma, mgwirizano ndi ngodya ya kukangana kwamkati kwa nthaka zimawerengedwa.

Kufotokozera kwa zida za triaxial

Sl.4. Triaxial zida

Chipangizo cha Triaxial (Chith.4) imakhala m’munsi mwa mbale ya m’munsi ya chipinda, chomwe chimayimira chitsanzo, ndi kumtunda kwa pisitoni kuti mutengere chitsanzo ndi mbale yapamwamba yomwe imatseka chipindacho. Zitsanzo zodziwika kwambiri ndi diameter ϕ=36 mm, kutalika h=2,2-2,5_ϕ_. Kutalika kwa chipindacho ndi D=135mm, kutalika H =180 mm. Kachubu yopapatiza K imayambira pakati pa choyimitsirachitsanzo1kukhetsa chitsanzo kuchokera pansi, chomwe chimalandira madzi kuchokera pachitsanzocho kudzera mu mbale ya porous ndikuchikhetsa kunja kwa chipindacho mu chubu lagalasi C.1. Ngati kuyesako kuchitidwa popanda kukhetsa chitsanzo, njira iyi imayesa kuthamanga kwa madzi mu pores. Pali njira K m’munsi mwa mkuwa wa chipindacho2kwa kotunga madzi misa kudzaza chipinda ndi kulenga ofananira nawo kuthamanga mu chipinda pa chitsanzo.

Kupyolera mu mbale yapamwamba ya chipindacho imadutsa chogwirira cha pistoni kuti mutenge chitsanzo. Chitsanzo m’chipindacho chimazunguliridwa ndi nembanemba ya mphira, yomwe imatambasulidwa pamapeto onse awiri ndipo imagwirizanitsidwa ndi pisitoni ndi maziko pogwiritsa ntchito mphete za rabara. Pakatikati pa pisitoni pali njira K3kwa kukhetsa chitsanzo kuchokera kumtunda.

Mbali za chipindacho ndi zomata ndi silinda ya Plexiglas yomwe imayikidwa pamwamba ndi pansi pa chipindacho kudzera m’mphete za rabala.

Chipindacho chimayikidwa pamalo olimba. Kukweza kwachitsanzo kwabwinobwino kumachitika kudzera pa lever yokhala ndi zolemera, zomwe nthawi zambiri zimakhala 1: 10. Dongosolo lokwaniritsa kukakamiza kwachitsanzo m’chipindacho chimakhala ndi botolo lamadzimadzi B, lomwe limabweretsedwa m’chipindacho pogwiritsa ntchito chubu, manometer yoyezera kuthamanga kwa mpweya ndi botolo lokhala ndi mpweya woponderezedwa. Wofananira amayikidwa pamwamba pa pisitoni kuti akweze sampuli kuti ayeze kukhazikika kwachitsanzo chomwe chapakidwa.

Kuthamanga kwapakati kwa madzi amadzimadzi m’chipindamo kungasinthidwe mwakufuna kwawo pogwiritsa ntchito mpweya wa mpweya mu botolo B, kudzera mu ma valve V1 ndi V2. Kupanikizika kumeneku kumayambitsa kupsinjika kopingasa mu zitsanzo σ2 ndi σ3, zomwe chifukwa cha gawo lozungulira lachitsanzo zimafanana σ2 = σ3.

Kuchuluka kwamadzimadzi kumatha kukhala madzi osungunuka kapena mafuta, omwe amawakonda kuti asindikize bwino, chifukwa madzi amatha kudutsa zomangira. Mothandizidwa ndi kuthamanga kwa mpweya mu botolo B, kuchuluka kwamadzimadzi kumadzaza chipindacho mpaka valavu V6, yomwe imatseka. Katundu woyimirira wachitsanzo P, chomwe chimasamutsidwa mosasunthika kupita kuchitsanzo kudzera pa chogwirizira pisitoni, chogawidwa ndi gawo lopingasa lachitsanzo A chimapereka kupsinjika koyima σ1 = P/A

Kuyesa kukanika kwa triaxial

Pachitsanzo choyesera, chimakonzedwa mu chipangizo china, kotero kuti chogudubuza chokhala ndi m’mimba mwake 36 mm, kutalika kwa 78 mm kapena 90 mm chimapezeka, pomwe miyala ya fyuluta imayikidwa kuchokera pamwamba ndi pansi ndikuyika nembanemba ya rabara. Ndiye chitsanzo pamodzi ndi miyala ya fyuluta imayikidwa pa choyimilira mu chipinda, malekezero, nembanemba za mphira zimakokedwa pamwamba pa choyimilira ndi pisitoni yonyamula ndikutetezedwa ndi mphete za rabara. Malinga ndi machitidwe a ma laboratories ena, monga Prof. Skempton ku London, kukhetsa kwachitsanzo m’chipindamo panthawi yoyesedwa kumafulumizitsidwa ndi kuyika mbali za chitsanzocho ndi pepala la fyuluta, lomwe limayikidwa pamaso pa nembanemba ya rabara. Chitsanzochi chikalowetsedwa m’zida ndipo silinda ya Plexiglas itakhazikika m’mbale zam’mwamba ndi zapansi, ndizotheka kuyesa, zomwe zitha kuchitidwa m’njira zingapo, monga izi:

1. Mayeso osasunthika. M’mayeserowa, kukhetsa kwachitsanzo sikuloledwa panthawi yogwiritsira ntchito lateral ndi vertical test, pamene ma valve V4 ndi V5 amatsekedwa.

2. Mayeso osakoka ndi kuphatikiza. Pogwiritsa ntchito kupanikizika kwapambuyo, chitsanzocho chimatsitsidwa (mavavu V4 ndi V5 ndi otseguka), pamene pakugwiritsa ntchito mphamvu yowonongeka, madzi saloledwa (V4 ndi V5 atsekedwa).

3_) Zitsanzo zokhetsedwa_. Chitsanzocho chimakhetsedwa kwa nthawi yonse ya mayesero (mavavu V4 ndi V5 ndi otseguka), kotero kuti kugwirizanitsa kwathunthu kumachitika ndipo palibe madzi opanikizika omwe amapangidwa mu pores panthawi yogwiritsira ntchito mphamvu yowongoka σ1. Mayesowa amatenga nthawi yayitali, makamaka ndi dothi losalowerera bwino, chifukwa kukweza koyimirira σ1 kuyenera kuchitidwa pang’onopang’ono ndipo kuphatikiza kuyenera kudikirira pagawo lililonse. Kuphatikiza apo, mayeso omwe atchulidwawa atha kuchitidwa ndi saturated ndi partially saturated samples_._

Potengera zotheka zomwe tatchulazi, kuyezetsa kukanika kwa triaxial kumatha kuchitidwa mosiyanasiyana ndikusinthidwa molingana ndi mtundu wa dothi lopakidwa.

Zida, kachitidwe, mayunitsi, makonda ndi mapatani omwe afotokozedwa amasamutsidwa kuchokera ku mbiri yakale. Mawuwo si kafukufuku wa geotechnical, protocol ya labotale, projekiti ya maziko, umboni wa kukhazikika kwa malo otsetsereka kapena pulani yakukumba. Chisankho cha zitsanzo ndi njira yoyesera, momwe madzi amathira ndi kuphatikizika, madzi apansi panthaka, kuchuluka kwa katundu, zivomezi ndi chitetezo chakukumba ziyenera kutsimikiziridwa pa nthaka ndi nyumbayo, malinga ndi malamulo apano, ndi labotale yoyenera komanso katswiri wovomerezeka wa geotechnical.