Kudziwa kulimba kwa nthaka

Chidziwitso chofunikira cha akatswiri: Nkhaniyi ndi ndemanga yophunzitsa zakale ndipo si kafukufuku wa geotechnical, mulingo wovomerezeka wa labotale, kuwerengera maziko kapena buku la malangizo. Mawu oyambirira, ndondomeko, magawo oyezera, miyeso, magulu ndi maumboni a “malamulo athu” adasamutsidwa popanda kuyang’ana kutsata miyezo ndi malamulo omwe akugwiritsidwa ntchito. Kuyeza nthaka, kusankha njira, kutanthauzira zotsatira ndi zisankho za mapangidwe ziyenera kuchitidwa ndi akatswiri ovomerezeka a geotechnical ndi labotale yoyenera ya chinthu ndi malo.

Mutu wakupukutika kwa dothi si gawo lazotsatsa zatsopano za Savo Kusić. Zomwe zimapangidwa panopa ndi mazenera amatabwa, mawindo a aluminiyamu amatabwa ndi zitseko zopangidwa mwamakonda. Pazenera lina kapena pulojekiti ya pakhomo, mukhoza kutumiza pempho la mawu.

Maziko a mayeso a oedometer

Kulimba kwa nthaka kumatsimikiziridwa ndi kuyesa kukanikizira komwe kumapewa kukulitsa mbali, komwe kumatchedwanso kuyesa kwa oedometer kapena kuyesa kophatikiza.

Kuyesedwa kumachitidwa ndi zitsanzo zosasokonezeka, ndipo nthawi zina ndi zosokoneza. Pachiyambi choyamba, chitsanzo choyesera chimatengedwa ndikukanikiza mphete zachitsulo kukhala chitsanzo chokulirapo, chosasokonezedwa, chomwe chimadyetsedwa mu chipangizocho pamodzi ndi mphete pambuyo podula chitsanzo chowonjezera ndikuwongolera malo ake ndi m’mphepete mwa silinda. Muzochitika zachiwiri, mpheteyo imadzazidwa ndi chitsanzo mu chikhalidwe chokhazikika pa zokolola ndipo mu chikhalidwe chimenecho imalowetsedwa mu oedometer.

Kuyesaku kumachitika pogwiritsa ntchito zida zomwe zidapangidwa koyamba ndi Terzaghi ndipo zimatchedwa Oedometer. Masiku ano, pali zomangira zosiyanasiyana za chipangizochi, koma zonse zimatengera mfundo yofanana, kuyesa kukanikiza kwa dothi lomwe lili ndi katundu woletsa kukulitsa.

Oedometer: kufotokozera kwa chipangizo

Mth. 1. Odometer

Oedometer imakhala ndi silinda yachitsulo yomwe chitsanzocho chili pakati pa miyala iwiri yosefera (mkuyu 1). Chitsanzocho chimalowetsedwa m’chidacho mu mphete yachitsulo yokhala ndi 7-10 cm ndi kutalika kwa 1-4 cm. Katundu P amasamutsidwa kupita ku chitsanzo kudzera pamwala wapamwamba. Pansi pa mwala wosefera m’munsi, pali ngalande pansi pa silinda yothira madzi kuchokera pachitsanzo kupita ku chubu cha capillary, komanso madzi. Popeza kupanikizana kwachitsanzo kumachitika chifukwa cha ma pores, chifukwa tinthu tating’onoting’ono tating’onoting’ono ndi madzi omwe ali m’mabowo sakhala osasunthika, ndikofunikira kuwonetsetsa kuti madzi atuluka kuchokera pachitsanzo panthawi ya mayeso, omwe amatheka pogwiritsa ntchito mwala wosefera, njira ndi chubu cha capillary.

Kumanzere kwa chipangizocho ndi chitoliro choperekera madzi ndi mpopi kutsogolo kwa silinda, pamene chubu cha capillary chili kumanja, ndi mpopi kumbuyo kwa silinda. The capillary chubu imathandizanso kudziwa kuchuluka kwa nthaka permeability k.

Kuyesa

Chitsanzocho chikaikidwa mu silinda ndipo zidazo zitasonkhanitsidwa, tsekani mpopi wakumanzere, madzi, ndi kutsegula mpopi wamanja, kuti madzi alowe mu chubu cha capillary. Ndiye katundu wa chitsanzo akuyandikira, omwe amagwiritsidwa ntchito pang’onopang’ono. Zinthu zotsatirazi nthawi zambiri zimagwiritsidwa ntchito:0,50;1,00;2,00;4,00;6,00kp/cm2ndi kupitirira mpaka nthaka yochuluka kwambiri yomwe ikuyembekezeka pansi pa nyumbayi, makamaka mpaka10kp/cm2, ndipo ndi madamu amatha kukhala ochulukirapo20kp/cm2. Pa mlingo uliwonse wa katundu, panthawi yogwiritsira ntchito, stopwatch imayambika komanso nthawi zina15“,30“,1’,2’,5’,15’,45’,2h5h24h, ndiye mopitilira apo24h, mpaka kuphatikizika kwa chitsanzo pansi pa mlingo umenewo wa katundu, kukhazikika kofanana mu zikwi za millimeter kumawerengedwa pa wofananira ndikulembedwa muzolemba. Kuphatikizika kumaganiziridwa kuti kwatheka ngati kukhazikitsidwa kwa chitsanzo ndi Δh ≤0,02 mmkwa nthawi ya24ola. Pambuyo pophatikizana, mlingo wotsatira wa katundu umagwiritsidwa ntchito ndipo ndondomeko yonse ikubwerezedwa mofanana ndi zina zotero mpaka mlingo womaliza wa katundu.

Mayeso ophatikizika omwe amalepheretsa kukulitsa kwapang’onopang’ono kumachitika ndikutsitsa ndikutsitsa, kuti adziwe zotanuka za nthaka. Titanyamula chitsanzocho kumlingo wina, timachitsitsa ndi pang’onopang’ono momwe timachikweza. Kuthandizira kumachitika pambuyo 2,0 kp/cm2, 4,0 kp/cm2 ndi 6,0 kp/cm2.

Monga lamulo, kuyesedwa kumachitidwa ndi chitsanzo pansi pa madzi, chomwe chimayikidwa pa chubu lagalasi lakumanzere pamtunda wa pamwamba pa chitsanzo mu chipangizocho. Kuyesa compressibility wa chitsanzo pamaso pa madzi zachitika pa chifukwa ichi, chifukwa mayeso amatenga nthawi yaitali ndi chitsanzo Dries pa nthawi imeneyo, chifukwa cha amene compressibility chitsanzo adzakhala m’munsi kuposa compressibility weniweni wa nthaka mu chikhalidwe chinyezi zachilengedwe. Kuonjezera apo, chinyezi cha nthaka chachilengedwe chikhoza kukhala chochuluka kuposa momwe chinalili panthawi yoyesa, makamaka pamene madzi apansi akukwera, zomwe zingapangitse kuti apatukane kwambiri ndi kukanikizana kwenikweni kwa nthaka panthawi ya madzi ochuluka.

Zotsatira zoyezetsa zimayikidwa pamitundu itatu ya zithunzi, zomwe ndi diagram yoponderezedwa, porosity coefficient change diagram ndi nthawi yokhazikitsa.

Chithunzi chofananira cha kupsinjika

Chithunzichi chimapezedwa ngati kukakamiza kwanthawi zonse kuyikidwa pa chitsanzo cha abscissa axis σ = P/A, pomwe P ndi katundu womwe ukuchitika pachitsanzocho kudzera pamwala wosefera wapamwamba mu kp/cm2, A ndiye gawo lagawo la abscissa lolumikizana ndi pulogalamuyo, sampuli yolumikizana ndi pulogalamuyo. Δh/h pamene Δh ndi kukhazikitsidwa kwa zitsanzo zomwe zili pansi pa katundu Δσ panthawi yophatikiza, h kutalika kwa chitsanzo musanalowetse (mku. 2).

Mth. 2. Chithunzi choponderezedwa chachibale

Pakutsitsa, chithunzi cha kukakamiza koyambirira a.

Panthawi yotsitsa, ngati madzi osalephereka amaloledwa, kotero kuti chitsanzocho chikhalebe pansi pa madzi panthawi yotsitsa, chimabwerera ku chikhalidwe chake choyambirira, mwachitsanzo, kutupa. Komabe, chitsanzocho sichibwereranso ku chikhalidwe chake choyambirira, zomwe zikutanthauza kuti zakhala zikusintha pulasitiki (zokhazikika) kuphatikizapo zotanuka. Choncho, pamenepa, chithunzi chotupa b chimapezeka panthawi yotsitsa. Komabe, ngati kuyezetsa kunachitika popanda kulandira madzi, m’malo mwa chithunzi chotupa, chomwe chimatchedwa diagram of elasticity.

Ngati chitsanzocho chakwezedwanso mutatsitsa, chojambula chachiwiri c chimapezeka. Chithunzi chotupa ndi chojambula chachiwiri choponderezedwa c chimapanga chipika cha hysteresis pakati pawo. Mu dongo, malupu a hysteresis ndi ofunika kwambiri, choncho mapindikidwe m’dera la kutupa ndi kuponderezedwa kwachiwiri (zithunzi b ndi c) sizimaganiziridwa kuti zotanuka, koma zosinthika, chifukwa sizifanana ndi katundu molingana ndi lamulo la Hooke. Zopindika pagawo loponderezedwa koyambirira (chithunzi a) pagawo lomwe sanabwerere ndizokhazikika (zosasinthika).

Dothi compressibility module

Kuchokera pa chithunzi cha kuponderezana kwachibale, timapeza molingana ndi lamulo la Hooke kupita ku Jung’s modulus of elasticity E pa zinthu zotanuka, modulus ya nthaka Ms

Ms = Δσ / (Δh/h) [kp/cm2],

kumene Δσ ndiko kukwezedwa kwa katundu, Δh/h ndiko kuphatikizika kofananirako, komwe kumatengedwa kuchokera ku chithunzi choyambirira cha kukakamiza a (mkuyu 2).

Kuphatikizika kwa dothi Ms kumasiyana ndi modulus ya elasticity E ya zinthu zotanuka, chifukwa Ms siimasinthasintha pa chinthu chimodzi koma imasinthasintha ndikuwonjezeka ndi katundu wamba σ. Choncho, mtengo umodzi wa compressibility modulus Ms ukhoza kuperekedwa kokha pa kapitawo kakang’ono ka nthaka yabwino Δσ. Ngati mtengo wa gawo Ms ndi wapamwamba, kupanikizika kwa nthaka kumakhala kochepa komanso mosiyana. Malinga ndi malamulo athu oyambira, mulingo wotsatirawu wa kuphatikizika kwa dothi m’malo ake achilengedwe amatsatiridwa:

Magulu omwe ali pansipa akupitilizidwa kuchokera ku zolemba zoyambirira, kuphatikizapo nthawi yobwerezabwereza 100-400 kp/cm2. Sizinafufuzidwe kapena kugwirizanitsa ndi malamulo omwe alipo.

Ms = 0 - 20 kp/cm2 dothi lolimba kwambiri

Ms = 20 - 50 kp/cm2 dothi lopindika kwambiri

Ms = 50 - 100 kp/cm2 dothi lapakatikati

Ms = 100 - 400 kp/cm2 dothi locheperako

Ms = 100 - 400 kp/cm2 dothi lothimbirika pang’ono

Ms = 400 - 1000 kp/cm2 dothi lothimbirika pang’ono

Ms > 1000        kp/cm2 dothi locheperako kwambiri.

Dothi elasticity module

Momwemonso, timapeza modulus ya kusungunuka kwa nthaka E:

E = Δσ / (Δh/h) [kp/cm2],

komwe kuwonjezereka kwapang’onopang’ono Δh/h kumatengedwa kuchokera ku chithunzi cha elasticity cha nthaka kuti chikhale chofanana ndi Δσ.

Dothi labwinobwino lophatikizidwa komanso lokhazikika

Sl.3. Chithunzi cha kusintha kwa porosity coefficient ya dothi lomwe lasokonekera

Ngati tiyesa kuyesa kwa oedometer ndi chitsanzo chosokonekera, chomwe tidalowa m’chidacho pamalo opangira zokolola, ndikukonza zotsatira za mayesowo pazithunzi zakusintha kwa porosity coefficient e kutengera kukakamiza σ (Mkuyu.3) mayendedwe ophatikizika amayimiridwa ndi zithunzi 1 kwa katundu woyamba, 2 kwa mpumulo, 3 pa katundu wachiwiri mpaka malire a zowonjezera zowonjezera σa ndi 4 kupitirira malire amenewo.

Chithunzi chothandizira2ndi chojambula chachiwiri cha compression3kupanga hysteresis kuzungulira kumbuyo komwe chithunzicho4akupitiriza kuwonjezera chithunzicho1, popanda kuswa, ngati kuti palibe kutsitsa ndi kukwezanso.

Sl.4. Chithunzi cha kusintha kwa porosity coefficient ya dothi losasokonezedwa

Komabe, ngati tiyesa oedometer mofanana ndi kale ndi chitsanzo chosasokonezedwa chotengedwa kuchokera kukuya kwa nthaka (mkuyu.4), chithunzi cha katundu wachiwiri3idzawonetsa pa katundu wina σb kusweka pamalo b, pambuyo pake chithunzicho chidzapitirira4kukhala ndi malo otsetsereka. Kuphulika kumeneku kunachitika chifukwa dothi lomwe chitsanzocho chinatengedwa linali pansi pa katundu wambiri p=γt kuposa katundu wa chitsanzo σ mu oedometer. Katundu wokwera p amachokera ku kulemera kwa zigawo zamtunda zomwe zilipo pamwamba pa nthaka, zomwe timazitcha kupanikizika kwa nthaka, kapena kuchokera ku katundu wa nthaka zakale zomwe zimatengedwa ndi nthawi ndi kukokoloka kapena kuchokera ku dothi la moraine kapena ayezi, zomwe timazitcha preload. Maonekedwe a overconsolidation makamaka khalidwe la dongo, kumene ife kusiyanitsa kawirikawiri consolidated ndi overconsolidated dongo.

Nthawi zambiri dongo lophatikizidwa

Dongo lokhazikika lomwe nthawi zambiri limakhala lozama pansi pa nthaka, lomwe silinawonekere kuti lilowetsedwenso. Chitsanzo cha dongo, yodzaza mu oedometer ndi katundu wamkulu kuposa kulemera kwa chapamwamba “dothi kuthamanga” zigawo, limasonyeza mosalekeza otaya kuphatikiza, popanda yopuma wachibale psinjika chithunzi kapena porosity koyefiyanti kusintha chithunzi. Kukhazikika kwa dongo ili pansi pa katundu wa chinthucho ndi chachilendo, mwachitsanzo, pansi pa katundu wina, kuthetsa kumachepetsa pakapita nthawi.

Dongo lophatikizana mopambanitsa

Dongo lophatikizika kwambiri limakhala lakuya kwambiri kapena linali litalowetsedwapo kale. Chitsanzo cha dongo chodzaza mu oedometer ndi kuthamanga kwambiri kuposa nthaka kuthamanga kapena preload limasonyeza fracture pa wachibale psinjika chithunzi kapena pa porosity coefficient kusintha chithunzi, otchedwa. geological fracture g, ndi kusintha kwakukulu kolowera (Mkuyu.5a). Kukhazikika kwa dongoli pansi pa kapangidwe kake ndi kakang’ono pakulemetsa komwe kuli pansi pa kukanikiza kwa dothi kapena kutsitsa σ1, koma imakhala yokulirapo pazambiri zomwe zili pamwamba pa σ1.

Ngati kupumula kwa geological sikunafotokozedwe bwino, ndiye kuti kumatsimikiziridwa pogwiritsa ntchito ma tangents pazithunzi (Mkuyu.5b).

Sl.5. _ Chithunzi cha kusintha kwa porosity coefficient of overconsolidated dongo_

Chiwonetsero cha nthawi yokhazikika

Chithunzichi, chomwe chimatchedwanso chithunzi chophatikizira, chimapezeka pamene, pamlingo uliwonse wotsitsa zitsanzo mu oedometer, nthawi t m’maola imagwiritsidwa ntchito ku abscissa axis, ndikukhazikika mu mm kumtunda wolumikizana (Chith.6a) kapena mu% ya ndalama zonse (mkuyu.6b).

Sl.6. Chidutswa cha Kuthetsa Nthawi

Dothi losamangidwa komanso lomangidwa limachita mosiyana ndi katundu. Dothi lotayirira, monga mchenga, lili ndi pores lalikulu, lomwe madzi amatuluka mofulumira pansi pa katundu, kotero kuti nthaka imakhazikika mofulumira, ndi kukhazikika kwakukulu komwe kumachitika kumayambiriro kwa katundu ndikufika kumapeto kwa katundu woperekedwa mu nthawi yochepa. Dothi lolumikizana monga dongo limakhala ndi timiyendo tating’ono tomwe madzi ndi ovuta kutulutsa atanyamula katundu. Pali magawo awiri mu nthawi yokhazikika ya dothi lokhazikika. Mu gawo loyamba, mwamsanga mutatha kugwiritsa ntchito katundu ku nthaka, popeza madzi sangathe kutuluka mu pores, amakhala opanikizika ndi kulandira katundu yense wogwiritsidwa ntchito. Mu gawo lachiwiri, madzi opanikizika a pore amayamba kukankhira kunja pansi pa kupsinjika kwake chifukwa cha katundu, omwe pang’onopang’ono amasamutsidwa ku dothi lolimba. Mu gawo lachiwiri ili, tinthu tating’onoting’ono timabwera palimodzi ndipo pores amachepa. Njira yochepetserayi imapitirira mpaka madzi opanikizika amakakamizika kuchoka mu pores, i.e. mpaka kupanikizika kwa madzi mu pores kutha. Chifukwa chake, kuphatikiza kwa dothi makamaka ndi vuto la hydrodynamic, lomwe limadalira kuchuluka kwa nthaka ndi porosity. Pankhani ya dongo, yomwe permeability yake ndi yochepa, njira yophatikizira ingatenge nthawi yayitali kwambiri, ndipo kuwonjezera apo, malo okhalamo angakhale aakulu kwambiri chifukwa cha porosity yapamwamba kwambiri kusiyana ndi mchenga. Pamaziko a mayeso ophatikizana, maphunziro a nthawi yokhazikika amatha kuwerengedwa kwa nthawi yonse ya kuphatikizika komanso m’magawo amodzi.