** Muhimmiyar bayanin kula na aminci:** Wannan ƙwararriyar rubutun ne, ba dakin gwaje-gwaje na yanzu ko jagorar filin ba. Hanyoyin da aka bayyana sun haɗa da mercury, buɗewar wuta, dumama, paraffin, da sauran kayan aiki da kayan da ka iya zama haɗari ko rashin yarda a yau. Kar a yi amfani da su ba tare da ingantattun ma’auni ba, ƙimar haɗari, takaddun bayanan aminci, dakin gwaje-gwaje masu dacewa da kulawar ƙwararru. Rubutun baya cikin tayin samfura da sabis na Savo Kusić na yanzu.
Ƙaddamar da nauyin nauyin ƙasa
Akwai hanyoyi da yawa na ƙayyade ma’aunin nauyi na ƙasa, wanda za mu kwatanta waɗanda aka fi amfani da su: hanyar silinda, hanyar da nutsar da samfurin a cikin ruwa, hanyar tare da nutsar da samfurin a cikin mercury, da kuma hanyar da yashi.
Tsari tare da silinda
Wannan hanya ita ce mafi yawan amfani da ita kuma ana yin ta a cikin filin da kuma a cikin dakin gwaje-gwaje. Ana shafa shi ga ƙasa mai ɗaure da kwance.
Ana danna silinda na ƙarfe na ƙarar da aka sani, tare da ƙaƙƙarfan gefen ƙasa, a cikin ƙasa ko cikin samfurin da ba shi da damuwa ko na wucin gadi, ta yadda ya cika da yawan ƙasa. Bayan haka, an daidaita saman samfurin tare da wuka tare da babba da ƙananan gefuna na silinda kuma nan da nan an rufe shi da murfin karfe kuma a auna a kan sikelin.
Idan W shine nauyin samfurin tare da silinda da iyakoki, W0 Nauyin Silinda kanta tare da murfi, V ƙarar silinda
Girman ƙasa γ shine:
γ = (W - WP) / V
Hanyar tare da nutsar da samfurin a cikin ruwa
Wannan hanya ta dogara ne akan dukiya ta zahiri cewa ƙarar jikin da aka nutsar a cikin ruwa daidai yake da ƙarar ruwan da aka yi gudun hijira. Ana amfani da shi kawai don ƙasa mai ɗaure, lokacin da ba za a iya samun samfurin siffar geometric na yau da kullum ba.
Daga cikin ƙasa mara kyau ko daga babban samfuri, ɗauki ɗan samfurin siffa mai siffar macaque kuma auna nauyinsa W a yanayin yanayinsa akan sikeli. Sa’an nan samfurin an rufe shi da paraffin da aka narke, wanda ba dole ba ne ya yi zafi sosai, amma kawai ya isa ya narke. Wani bakin ciki na paraffin1-2 mmyakamata ya rufe duka samfurin gaba daya. Sannan ana auna samfurin tare da paraffin akan ma’auni kuma ana samun nauyin W’. Nauyin paraffin shine W’ - W.
Ana samun ƙarar paraffin VP daga dabarar: VP * γP = W’ – W,
inda γP shine ma’aunin nauyin paraffin, wanda aka sani kuma yayi daidai γP =0,892p/cm3.
Daga lissafin da ke sama muna da: VP = (W’ – W)/0,892 cm3]
Sl.1. Yin tantance yawan nauyin ƙasa ta hanyar nutsar da samfurin cikin ruwa
Sa’an nan, samfurin da aka nannade paraffin an rataye shi a kan ma’auni tare da zaren siliki na bakin ciki (fig.1), an daidaita ma’auni, sa’an nan kuma an zana jirgin ruwa tare da ruwa mai tsabta a ƙarƙashin samfurin, don haka duk samfurin ya nutse cikin ruwa. Tunda, saboda bayyanar rashin nauyin samfurin a cikin ruwa, ma’auni a kan sikelin yana damuwa, an sake kafa shi ta hanyar cire ma’auni, don haka an samo nauyin samfurin tare da paraffin da aka nutsar a cikin ruwa W. Bambanci a cikin nauyin samfurin tare da paraffin a cikin yanayin da ba a cika ba da kuma nutsewa yana ba da nauyin ruwan da aka yi hijira, watau idan nauyin nauyin ruwa ya kasance YW =1,00, yawan ruwan da aka raba Vw
Muna cire ƙarar paraffin VP daga ƙarar Vw, kuma muna samun ƙarar samfurin.
Girman nauyin ƙasa shine: γ = W/(Vw – VP)*m
inda m shine madaidaicin gyara saboda bambancin zafin ruwa, tunda Y =1,0ga zafin ruwa a4 °C: m = γw, T / γw,4oC.
Tsari tare da nutsar da samfurin a cikin mercury
Ana amfani da wannan hanya don ƙasa mai ɗaure, kuma a cikin lokuta inda ya zama dole don daina ɗaukar samfurin nau’in siffar geometric na yau da kullum, wanda shine lamarin, alal misali, lokacin ƙayyade iyakokin ƙasa na shrinkage.
Sl.2. Yin tantance yawan nauyin ƙasa ta hanyar nutsar da samfurin a cikin mercury
An nutsar da samfurin a cikin wani jirgin ruwa cike da mercury gaba ɗaya (Fig.2) da kuma amfani da farantin gilashin da siraran ƙarfe na ƙarfe, ana matse shi ta yadda za a nutsar da shi gaba ɗaya a cikin mercury. Ana zuba mercury da aka danne a cikin babban jirgin ruwa, daga inda ake ɗaukar nauyinsa kuma a auna shi. Idan W shine nauyin samfurin, Wz shine nauyin mercury da aka raba, γz shine nauyin mercury, Vz= V shine adadin mercury da aka raba wanda yayi daidai da girman samfurin;
Vz * γz = Wz * Vz = Wz/ γz
to babban yawan kasa shine:
γ =W*γz /Wz.
Hanyar da yashi
Ana yin wannan gwajin a cikin filin kuma galibi ana amfani da shi ga ƙasa mara iyaka, tsakuwa, yashi mai tsakuwa, kayan moraine da sauran lokuta, lokacin da cire samfuran da ba su da damuwa tare da silinda ba zai yiwu ba. Ka’idar wannan hanya ta ƙunshi tono rami a cikin ƙasa sannan kuma cika shi da yashi na al’ada na nau’in nau’in nau’in nau’in nau’in nau’in nau’in nau’in nau’in nau’in nau’in nau’in nau’in nau’in nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i nau’i). An ƙayyade nauyin nauyin ƙasa daga nauyin nauyin da aka tono da kuma girman ramin.
An daidaita saman ƙasar, wanda za a tantance girman girmansa, an daidaita shi ta yadda ya kasance a kwance, sannan farantin kwano kusan.40x40 cm(fig.3), tare da samfurin da aka yanke a tsakiyar diamita Ø =20 cm, kauri5 mm, don haƙa rami a ƙasa. Farantin yana kwance a ƙasa kuma a gyara shi da turaku. Ramin da diamita na20 cm, zurfin kusan20 cm, Zai fi dacewa tare da ganuwar tsaye, amma ba a waje da samfurin ba kuma tsaftace da kyau. Ana ajiye duk kayan da aka tono akan farantin, sannan nan da nan bayan an tono, alhalin yana da zafi, sai a auna shi akan sikeli kuma ana tantance nauyinsa W. Don daga baya don ƙayyade yanayin zafi na yanayi, ana sanya samfurin a cikin akwatin kwano tare da murfi, don ɗauka zuwa ɗakin bushewa bayan an gama aikin filin. Nan da nan, ana zuba yashi na al’ada busasshen a cikin ramin da aka tono, wanda nauyinsa γd ana aunawa ne ta hanyar aunawa, watau daga gwajin dakin gwaje-gwaje da aka yi a baya, ta hanyar zubar da yashi ta mazurari daya kuma daga tsayi iri daya, h ya fadi kamar yadda a cikin gwajin filin.
Sl.3. Yin tantance yawan nauyin ƙasa ta amfani da gwajin yashi
Kafin fara gwajin, auna nauyin yashi na yau da kullun a cikin kofuna masu aunawa, sannan bayan cika ramin da ke cikin ƙasa da wannan yashi zuwa saman saman farantin gwangwani, wanda aka daidaita shi da mai sarrafa karfe mai tsayi.40 cm, auna sauran yashi a cikin beaker, ta yadda za a samu ainihin nauyin Wd na busassun yashi na al’ada a cikin rami zuwa saman saman takardar. Ƙirar Vd na rami da aka tono har zuwa saman saman takardan takarda an ƙaddara bisa tsarin Vd = Wd/γd.
Ana samun ƙarar V na rami a cikin ƙasa ta hanyar rage ƙarar v na buɗe samfurin tin:
Ma’aunin nauyi na ƙasa γ shine: γ = W/V, inda W shine nauyin ƙasa da aka tono daga ramin da aka auna nan da nan bayan hakowa. An lura cewa ana amfani da filasta, mai ko kwalta mai sanyi maimakon yashi, wanda ba ya da hankali a yanayin damina. Bugu da ƙari, akwai kuma na’urori na musamman don sauƙi da sauri aiki akan gwaji tare da yashi.
An ba da kimanin ƙimar ma’aunin nauyi na ƙasa a cikin tebur1, tare da bayanin kula cewa a cikin nazarin geomechanical a kowane hali, ya kamata a ƙayyade nauyin nauyin ƙasa ta hanyar gwaji a cikin dakin gwaje-gwaje ko a filin.
Tabbatar da danshin ƙasa
Ana yin ƙoƙari na ƙayyade danshin ƙasa ta hanyoyi da yawa, wato ta hanyar dakin gwaje-gwaje ta amfani da na’urar bushewa ta lantarki, hanyoyin filin ta yin amfani da bushewa a kan bude wuta, ta amfani da carbide, aunawa karkashin ruwa da kuma amfani da pycnometer na iska. A nan za mu bayyana kawai hanyoyin biyu na farko, waɗanda aka fi amfani da su a ƙasarmu.
Hanyar dakin gwaje-gwaje ta amfani da na’urar bushewa
Wannan hanya ita ce mafi aminci kuma mafi yawan amfani da ita ga kowane nau’in ƙasa. Ana sanya wata ƙasa daga samfurin da ba ta da matsala a tsakanin gilashin da ba a taɓa gani ba, wanda ake kira hourglasses, ana ɗaure su da manne da ƙarfe kuma a auna su tare da ma’aunin nazari, sannan a sanya shi a cikin na’urar bushewa ta lantarki inda aka bushe ta.105°Czuwa nauyi akai-akai (fig.4). Bambanci a cikin zafin jiki lokacin bushewa bai kamata ya fi ± girma ba2°C, Tun da a ƙananan zafin jiki cikakke bushewa ba a aiwatar da shi ba, kuma a mafi yawan zafin jiki na kwayoyin halitta a cikin samfurin na iya ƙonewa. Matsakaicin lokacin bushewa na samfurin tare da gilashin sa’a guda a cikin na’urar bushewa shine yashi kusan6hours, kuma ga yumbu kimanin12hours. Bayan bushewa, samfurin da aka rufe a cikin gilashin sa’o’i tare da manne ana sanya shi a cikin injin daskarewa don kwantar da zafin jiki, bayan haka an sake auna shi.
Sl.4. Sample bushewa cikin gilashin sa’a tare da manne
Idan W shine nauyin samfurin a yanayin yanayin danshi tare da gilashin sa’a da matsewa, Ws nauyin samfurin a cikin busassun yanayi tare da gilashin sa’a da matsewa, Wt nauyin gilashin sa’a da matsewa, danshin ƙasa w bisa ga ma’anar Atterberg shine nauyin ruwa da aka raba da nauyin ƙasa a cikin busasshiyar ƙasa, wato: w W_ Ws-Wt*100[%].
Ƙaddamar da porosity na ƙasa da ƙayyadaddun porosity
Ana yin gwajin a kan samfurin da ba a damu ba, muddin za a iya ƙayyade girmansa a cikin yanayin rashin damuwa.
Muna danna silinda na ƙarfe na ƙarar da aka sani a cikin ƙasa mara kyau ko cikin samfurin mafi girma, daidaita saman saman samfurin tare da gefuna na Silinda kuma sanya shi ya bushe.105°Char sai nauyin ya kasance akai-akai, sa’an nan kuma bar shi ya huce a dakin da zafin jiki, kuma a sake auna shi akan ma’auni tare da silinda.
Idan V shine girman ciki na silinda, Vm shine girman daskararrun ƙasa ba tare da pores ba, Wd shine busassun nauyin samfurin, γs shine girman nauyin ƙaƙƙarfan ƙwayoyin, ƙarancin ƙasa n shine
Muna ƙayyade ƙarar Vm dangane da bushewar nauyin samfurin Wd:
wato, a cikin kaso na jimlar yawan ƙasa
Tun da γd = Wd/V, i.e. bushewar nauyin ƙasa, ana iya sanya shi
n =100* (1- γd/ γs) [%].
Ana samun ƙididdiga na porosity daga nau’in e = n/ (1-n).
Don ƙira, sarrafa inganci ko aiwatar da ayyuka, yi amfani da ƙa’idodi na yanzu, daidaitattun hanyoyin gwaji da dakin gwaje-gwaje mai izini. An adana wannan rubutu a matsayin tushen ilimi na tarihi.