Masiku ano, Savo Kusić amayang’ana kwambiri mazenera amatabwa, mazenera a matabwa a aluminiyamu, mazenera amwambo, khomo ndi zopempha za mawu. Mawuwa akadali akale a geotechnical archive ndipo si mwayi wopanga makoma osungira, kufufuza kwa geotechnical kapena earthworks.
Njira zodziwira kupanikizika kwapadziko lapansi
Kuthamanga kwa dziko lapansi kumawonekera pokhapokha pamene kusinthika kwa khoma kumtunda kuli kwakukulu kokwanira kuti ayambe kutsutsa mkati mwa nthaka, yomwe imatsutsana ndi mphamvu yakunja. Franzius adakhazikitsa zoyeserera kuti kuti ayambitse kukakamiza kwapadziko lapansi, ndikofunikira kusuntha khoma ngati mchenga wonyowa s=30_h_1,5, ndi mchenga pansi pa madzi s=23h2,5kumene kusamuka s kuli mm, ndipo h ndi kutalika kwa khoma mu m. Choncho, ngati kutalika kwa khoma ndi h=3,0 m, kuti mutsegule kupanikizika kosasunthika, pakakhala mchenga wonyowa, m’pofunika kusuntha khoma molunjika pansi s=156 mm. Komabe, popeza kusuntha kwakukulu kwa khoma sikuloledwa nthawi zambiri, kumayendetsedwa m’njira izi:
a) Ngati kutalika kwa khoma kuli kochepa, monga momwe zilili ndi maziko a CD (mkuyu.1a), kungokhala padziko lapansi kuthamanga Ep si kuganiziridwa, malinga ngati wosanjikiza dothi, kutsogolo kwa phazi CD akhoza kenako kufukulidwa kapena kukokoloka, ndipo masamutsidwa kokha ndi yogwira lapansi kuthamanga Ea pa msinkhu wonse wa khoma AB.
b) Pankhani ya kutalika kwa khoma (Chith.1b), m’malo mwa kukakamiza kwapadziko lapansi Ep kumbali ya khoma CD, Ea imatengedwa ngati kukana komwe kumatsutsana ndi mphamvu _Ea1_ndi E2.
c) Pankhani ya ma struts omwe amafunikira kulandira mphamvu zazikulu zopingasa, kukakamiza kwathunthu Ep kumafunika pamtunda wonse wa khoma AB, pofuna kutsutsa gulu lankhondo R (mkuyu.1c). Zikatero, dothi limapunduka koyamba pogwiritsa ntchito ma jacks a hydraulic, ndipo ngati dothi lili ndi dongo lofewa kapena zinthu zofananira zomwe zimapindika mwamphamvu pansi pa katundu, nkhaniyi imasinthidwa m’lifupi mwake b ndi miyala ya miyala, yomwe mbali yake ya mikangano yamkati ndi yayikulu ndipo imatha kupindika mosavuta, kotero kuti pambuyo pake zopindika za nthaka pansi pa katunduyo zimachotsedwa.
Sl.1. Nkhani zokhuza mphamvu yapansi panthaka
Pali njira zingapo zodziwira kupanikizika kwapadziko lapansi, zomwe zimadziwika bwino ndi njira za Coulomb ndi Rebhann-Poncelet.
Njira yojambulira ya Coulomb
Malingana ndi njirayi, malo enieni otsetsereka amatengedwa, komanso kuti kukana kwamkati kwa nthaka kumangokhalira kukangana, popanda kugwirizana (c=0). Popeza kupanikizika kwapadziko lapansi kumawoneka ngati mphamvu yotsutsa, awa ndi ngodya ya kukangana kwamkati kwa nthaka ndi ngodya ya kupatuka kwa mphamvu Ep kuchoka pachizolowezi kupita kukhoma la chizindikiro china, mwachitsanzo -δ ndi -ϕ (mkuyu.2a).
Ngati mkati mwa khomalo ndi AB ndipo ngati titengera malo otsetsereka AC, mphamvu yakunja Ep imatsutsidwa ndi kulemera kwa W kwa prism yotsetsereka ABCA ndi kukana kwa frictional Q pamtunda wotsetsereka AC. Popeza kulemera W kumadziwika ndi kukula, mayendedwe ndi mayendedwe, pomwe mphamvu Q ndi Ep zimadziwika ndi chitsogozo ndi chitsogozo, ndizotheka kupanga dongosolo la mphamvu (Mkuyu.2b), pomwe kukula kwa mphamvu Ep kumatsimikiziridwa.
Sl.2. Coulomb Passive Earth Pressure
Komabe, popeza kupanikizika kochepa kwambiri Ep,min kumafunika, komwe kumayenderana ndi malo otsetsereka AC, pomwe prism yotsetsereka imatha kupanga ndikukankhira kunja kwambiri motengera mphamvu yakunja, zimachitika motere (mkuyu.3).
Sl.3. Kutsimikiza kwa passive earth pressure EP ndi Coulomb
Malo angapo otsetsereka mokhazikika AC amajambula1, AC2AC3 ndi. . . ndipo pa prism iliyonse yotsetsereka zindikirani kulemera kwake W1= _AΔABC1_x1,00x γ, W2= _AΔABC2_x1,00x γ, W3 = AΔABC3 x1,00x γ. Kenako, pa prism iliyonse, dongosolo lolingana la mphamvu limapangidwa ndipo mphamvu EP zimatsimikiziridwa.1, EP2, EP3… Mphamvuzi zimagwiritsidwa ntchito mu chiŵerengero choyenerera ku chithunzi cha mphamvu EP ndipo tangent ku chithunzichi chofanana ndi abscissa axis imapereka mtengo wochepa kwambiri Ep, womwe umagwirizana ndi malo ovuta kwambiri AC. Choyipa cha njirayi ndikuti, chifukwa cha yankho lake lojambula, limatha kupereka mphamvu Ep yomwe imapatuka kwambiri ku zenizeni. Choncho, njira imeneyi si ntchito kawirikawiri.
Njira yojambula ya Culmann
Malinga ndi njirayi, zimaganiziridwa kuti kupanikizika kwapadziko lapansi Ep kumachita mozungulira -δ ndi yachilendo ku khoma lothandizira, kuti mzere wa malo otsetsereka a nthaka umadutsa ngodya -ϕ ndi yopingasa, ndi kuti mzerewu umadutsa ngodya -(δ+ϕ) ndi mzere wa khoma (mkuyu.4a). Pakufanana kwa malire mphamvu zitatu zochitira W, Q ndi Ep zimadutsana panthawi imodzi. Popeza mphamvu W imadziwika ndi mayendedwe ake, kukula kwake ndi mayendedwe ake, ndi mphamvu Q ndi Ep ndi chitsogozo chake ndi malangizo ake, titha kujambula dongosolo la mphamvu (mkuyu.4b). Ngati titembenuza makona atatu awa a mphamvu mozungulira90°- ϕ motsatana ndi mawotchi, mphamvu W idzagwera motsatira mzere wa malo otsetsereka a nthaka AN, mphamvu Q polowera kumalo otsetsereka AC, ndi mphamvu Ea molunjika mzere wa malo BH, popeza pakati pa mphamvu W ndi _Q_α pali mbali ya W+ ndi Q_α Q ndipo yachilendo kukhoma pali ngodya δ, kotero komwe mphamvu Ep imayenderana ndi momwe mzerewo umakhalira BH (mkuyu.4a).
Sl.4. Kutsimikiza kwa kupanikizika kwapadziko lapansi ndi Coulomb
Njira yodziwira kupanikizika kwapadziko lapansi ndi motere (mkuyu. 4c). Kuchokera pamyendo wa khoma A timajambula malo angapo otsetsereka AC1, AC2, AC3…. Chilichonse mwa malowa chikufanana ndi prism yotsetsereka ABC1, ABC2, ABC3…, amene utali wake perpendicular zolembedwa timaganiza kukhala ofanana ndi umodzi. Ngati zolemera za prisms zadothi izi W1= _AΔABC1_x1,00x γ, W2= _AΔABC2_x1,00x γ, W3= _AΔABC3_x1,00x γ, kumene γ ndi kulemera kwa volumetric kwa nthaka, yogwiritsidwa ntchito pamzere wa malo otsetsereka a nthaka AN, tidzapeza mfundo I, II, III … Pojambula mizere yofanana ndi mzere wa malo kuchokera ku mfundozi, timapeza mfundo zodutsamo R1, R2, _R3…Matatu A_I_R1, A_II_R2, A_III_R3 ndi ndege zamphamvu W, Q ndi Ep pamalo otsetsereka. Polumikiza mfundo R1, R2, R3… timapeza mzere wa Cullmann wa zovuta zapadziko lapansi, zomwe zimatchedwa Cullmann’s Ep Line. Tanjenti ku mzerewu wofanana ndi mzere wa malo otsetsereka a nthaka amapereka utali wochepa kwambiri KK’, womwe molingana ndi mphamvu W umapereka mphamvu yapadziko lapansi Ep.
Tikakulitsa njira AK podutsana ndi mzere wamtunda, timapeza malo otsetsereka osakanizidwa pang’ono AC.
Njira ya Rebhann-Poncelet
Malingana ndi njira iyi, ndondomekoyi ndi yofanana ndi yodziwira kuthamanga kwa dziko lapansi ndi kusiyana komwe mphamvu Q imachita pa ngodya -ϕ ndi yachibadwa mpaka pamtunda wotsetsereka, ndi mphamvu Ep pa ngodya -δ ndi yachibadwa ku mzere wa khoma. Malinga ndi Rebhann, AΔABC = AΔACD (mkuyu.5a). Njira yodziwira kupanikizika kwapadziko lapansi ndi motere:
Sl.5. Kutsimikiza kwa kupanikizika kwapadziko lapansi molingana ndi Rebhann-Poncelet
Kuchokera ku phazi la khoma A timajambula mzere wa malo otsetsereka a nthaka pamtunda -ϕ ndi yopingasa.
Kuchokera pamwamba pa khoma B timajambula mzere BH pa ngodya -(δ+ϕ). Pa M pa mphambano ya malo ndi malo otsetsereka apansi, zachibadwa zimakwezedwa ku mphambano L ndi semicircle pamwamba pa AN ngati m’mimba mwake.
Ndi kutsegula kwa kampasi AL, timasamutsa mfundo L kupita ku D (AL=AD).
Pojambula kuchokera ku nsonga D kufanana ndi mzere wopita ku mphambano C ndi mzere wamtunda, timapeza mbali imodzi ya katatu yapadziko lapansi DC = e. Kusamutsa nsonga C kupita ku F (DC= DF) ndikutsitsa CK yachibadwa ku mzere wa malo otsetsereka a nthaka, timapeza mphamvu ya katatu ya dziko lapansi DCF, komwe timapeza Ep=1/2_γ_ ef, pomwe γ pali makulidwe a nthaka.
Mzere AC ukuyimira malo otsetsereka. Chithunzi chapansi papansi ndi ba (Mkuyu.5b). Imapezedwa pamaziko a mawonekedwe
Ep = xh/2, kuchokera x =2_Ep_/h
Malo owukira amphamvu Ep ali pamtunda wapakati pa mphamvu yokoka ya makona atatu abc. Mphamvu Ep imachita pa ngodya -δ ndi yofanana ndi khoma lotsekera.
Njira zomwe zanenedwa, mayunitsi, mafomula ndi zikhalidwe zimasamutsidwa kuchokera ku mbiri yakale ndipo sizilowa m’malo mwa kafukufuku wa geotechnical, mawerengedwe osasunthika, projekiti yosunga khoma kapena dongosolo lakupha. Kuthekera kwa kulimbikitsa kukana kumadalira mapindikidwe ololedwa, magawo enieni ndi kusanjika kwa nthaka, pansi pa nthaka ndi madzi apamtunda, ngalande, katundu wowonjezera, kukhudzidwa kwa chivomezi, kukokoloka, kukumba, magawo omanga ndi nyumba zoyandikana nazo. Yankho la malo enaake liyenera kutsimikiziridwa ndi kafukufuku woyenera ndi akatswiri ovomerezeka a geotechnical ndi zomangamanga malinga ndi malamulo omwe alipo.