Maumbirwo evhu
Pasi pechimiro chevhu kunorehwa kurongeka kwechikamu chakasimba muviri wevhu. Sezvinozivikanwa, ivhu rinoumbwa nezvidimbu zvakasimba nemapori akazadzwa nemvura, mhepo kana mhute yemvura, kazhinji chikamu nemhepo chikamu nemvura. Zvinoenderana nerongero yezvimedu zvakasimba muvhu ndipo panotsanangurwa chimiro charo. Zvimiro zvevhu risina kusungwa uye chevhu rakasungwa zvinosiyana zvikuru pakati pazvo.
Chimiro chevhu risina kusungwa
Chimiro chevhu risina kusungwa chinoumbwa pasi pesimba regiravhiti. Zvimedu zvakasimba zvevhu iri zvakakura uye zvinodonha pasi, zvichigadzikana pasi pesimba regiravhiti, nepo masimba okukwezvana pakati pemamorekuru ezvimedu zvakadaro asipo kana kuti madiki zvikuru uye anokundwa negiravhiti. Nokuda kweizvozvo, muvhu risina kusungwa zvimedu zvakasimba zvinoiswa padhuze nepadhuze, zvichizadza nzvimbo isina chinhu iri pakati pezvimedu zvakarongedzwa (muf. 1_a_). Kana zvimedu zvevhu risina kusungwa zviri pedyo nechimiro chakatenderera uye zvehukuru humwe chete, sezvingaitika mujecha rine kuumbwa kwakafanana, ipapo chimiro chingava chakanyatsosimba (muf. 1_b_) kana kuti chakapfava zvikuru (muf. 1_c_), zvinoenderana nekugoverwa kwezvimedu zvakasimba muvhu. Chimiro chakanyatsosimba chinoenderana nekugona kukuru kwekusimba kwevhu risina kusungwa uye porosity yaro ndeye nmin=26%. Chimiro chakapfava zvikuru chinoenderana nekugona kuduku kunobvira kwekusimba kwevhu risina kusungwa uye porosity yaro ndeye nmax=48%. Saka semuenzaniso jecha rakasununguka remadune rine n=47%.
Sl. 1 Chimiro chevhu risina kusungwa
Kana ivhu risina kusungwa riine hukuru hwakasiyana hwezviyo, zvekuti zvidimbu zviduku zvinadza nzvimbo dzisina chinhu pakati pezvikuru (sl. 2), porosity yevhu inova diki zvikuru (n=20% uye pasi ipapo).
Muf. 2. Chimiro chevhu risina kusungwa rine hukuru hwakasiyana hwezviyo
Chimiro chevhu rakasungwa
Muvhu rakabatanidzwa chimiro chakasiyana pane chemuvhu risina kusungwa. Muvhu rakabatanidzwa panoonekwa masimba ekubatana, ayo akasimba kupfuura simba regiravhiti rezvimedu zviduku uye anoanamatira panzvimbo dzavanobatana. Nokudaro, zvimedu izvi hazvidonhi pasi zvichitevedzana, asi zvinoramba zvakanamatirana chimwe pamusoro pechimwe uye chimwe parutivi pechimwe (fig. 3_a_), zvichiita chimiro chakaita cheni semambure (fig. 3_b_), chakaita mapfufu (fig. 3_c_) nezvimwewo, zvinonzi zvimiro zvechinzvimbo chepamusoro. Zvimiro zvakadaro zvine porosity huru, inogona kusvika 60-80% yehuremu hwese, izvo zvisingagoneki muvhu risina kusungwa.
Sl. 3. Chimiro chevhu rakasungwa
Porosity uye coefficient ye porosity
Porosity yevhu inotsanangurwa nechiyero chevhoriyamu yema pore ichienzaniswa nehuwandu hwese hwevhu (fig. 4).
Muf. 4. Porosity uye coefficient yeporosity yevhu
Kana tikaratidza na
- Vp = vhoriyamu yemaporo muvhu
- Vm = huwandu hwezvimedu zvakaoma
- V = huwandu hwese hwevhu,
porosity yevhu n inotsanangurwa se
n = VP / V = VP / (VP + Vm),
kureva kuti muzana yeuwandu hwese hwevhu
n = 100 * VP / (VP + Vm) %.
Coefficient yeporosity yevhu inotsanangurwa sehukama hwevhoriyamu yemaporesi kune vhoriyamu yezvimedu zvakasimba:
e = VP / Vm.
Kubva pamuenzaniso weporosity n tine:
nVP + nVm = VP, kubva ipapo Vm = VP(1-n) / n.
Tichitsiva kukosha uku mufomura ye e tinowana
e = n / (1-n).
Kubva paequation iyi tinowana
e - ne = n; n = e / (1 + e).
Koefishienti ye porosity inoratidza kuwanda kwevhu. Kana koefishienti e yakakura, kuwanda kwevhu kunova kudiki uye zvinopesana. Kana ivhu rinotambanuka richigara pasi pemutoro, kuburikidza nekoefishienti ye porosity pamberi nepashure pekugara pasi panogona kuonekwa ukuru hwekugara pasi Δ_h_.
Ngatitarisei rukoko rwevhu rinotsikiririka rine ukobvu h (fig. 5_a_). Kana rukoko urwu rwakatakurwa, ruchanyura pasi neurefu Δ_h_, zvekuti ukobvu hwaro hunodzikira nekuda kwemutoro ku h1. Saka
Δ_h_ = h – h1.
Sezvo kugara pasi kwevhu rinomanikidzikira kuchiitwa nekuda kwemapore, nokuti zvidimbu zvakasimba hazvidzikisiki zvinenge zvisingaiti, uyezve nemvura, kana mapore evhu azadzwa nayo zvishoma kana zvizere, saka kugara pasi uku kunogona kumiririrwa schematically pamuf. 5_b_.
Muf. 5. Kugara pasi Δh kwechikamu chevhu chinotsikiririka chine ukobvu h _ pasi pemutoro
Kana tikadoma ne h0 urefu hwekufungidzira hwerukoko rwezvimedu zvakasimba risina maporesi, rinonzi kureba kwakaderedzwa, ipapo tinogona kuratidza kugadzikana Δ_h_ maererano nekureba kwakaderedzwa h0 nechiyero ichi:
Kana tikatarisa rukoko rwevhu rine upamhi nehurefu zvakaenzana neimwe, ipapo urefu h, h1 ne h0 hunomiririra mavhoriyamu, uye naizvozvo
apo e iri koefishenti yeporosity pamberi, e1 mushure mekugara. Kubva pane zviri pamusoro panowanikwa kugara
Δ_h_ = h0 (e-e1).
Kuderera kunogona kuratidzwa zvichienderana nekukwirira kwedhiri h isati yaderera kana tikatsiva ukoshi hwekukwirira kwakaderedzwa h0:
h0 = h – nh = h (1-n) = h / (1+e),
sezvo n = VP / V = VP / h_,_ kubva ipapo VP = nh.
Saka zvinobuda
Mhando dzakasiyana dzevhu dzine zvinotevera avhareji kukosha kweporosity n uye coefficient ye porosity e:
Unyoro hweivhu
Mhando dzemvura iri muvhu
Mvura iri muvhu inoonekwa muchimiro chemvura iri mumapores pakati pezvimedu zvakasimba inonzi mvura yeporosi, ipapo se mvura yakasorwazve pazvimedu zvakasimba uye se mvura yekuvaka chimiro.
Mvura yepori inoumbwa ne mvura yakasununguka iri pakati pezvimedu zvakasimba, kufamba kwayo kuchiitwa maererano nemutemo waDarcy, vozotevera mvura yegiravhiti, inofamba pasi pesimba regiravhiti kubva kumusoro ichienda pasi mumativi ose, asi kufamba kwayo hakuitwi maererano nemutemo waDarcy, mvura yekapirari inofamba pasi pesimba remasimba ekapirari, uye mvura yekumanikidzwa kwepamusoro, inobatwa nekumanikidzwa kwepamusoro mumakona ari pakati pezvimedu zvakasimba zvevhu uye inonziwo mvura yepori yemakona. Mvura iyi yese inogona kubviswa zvachose nekuomesa ivhu patembiricha ye 110oC.
Mvura yakasorwazve ndiyo inofukidza zvimedu zvakasimba, izvo yakasungwa nazvo nemasimba emamorekuru. Iyi ndiyo inonzi firimu remvura, ukobvu hwayo huri 6-80 µµ (1µµ=10-6 mm, milimikron). Mvura yakasorwazve ine mhedzisiro shoma pazvimedu zvikuru, asi kana zvimedu zvidiki, mhedzisiro yayo inowedzera, nokuti nzvimbo yese yezvimedu inowedzera uye pamwe nayo chiyero chemvura yakasorwazve kune zvimedu zvakasimba pahuwandu hwevhu. Mvura iyi inogona kungobviswa zvishoma chete nekuiomesa pa 110oC.
Mvura yekuvaka chimiro yakasanganiswa nemakemikari mumakristaro emaminerari ezvimedu zvakasimba zveivhu. Mvura iyi ishoma zvikuru uye haigoni kubviswa nekusausa ivhu. Saka mvura iyi inogona kutorwa sechikamu chinoumba chidimbu chakasimba.
Huwandu hwemvura muvhu
Maererano netsananguro, huwandu hwemvura muvhu kana kuti mwando wevhu chiyero chehuremu hwemvura iri muvhu zvichienzaniswa nehuremu hwezvinhu zvaro zvakasimba. Maererano nehuwandu hwemvura muvhu pane zviitiko zvitatu: ivhu rakazara chose nemvura, ivhu rakazara zvishoma nemvura uye ivhu rakaoma chose.
Ivhu rakazara zvachose nemvura
Kana tikaratidza n seporosity yevhu, γs huremu hwevhoriyamu hwezvimedu zvese, γw huremu hwevhoriyamu hwemvura, ipapo hunyoro hwevhu rakazara wZ hunogona kuratidzwa nemutemo unotevera
Ivhu rine mvura zvishoma
Kana tikaratidza ne Ww huremu hwemvura iri muvhu, ne Wd huremu hwezvimedu zvakasimba, kureva huremu hwakaoma hwevhu, ipapo mwando wevhu w
w = Ww / Wd , kana kuti muzana rehuremu hwakaoma hwevhu: w = 100 Ww / Wd.
Muchiitiko ichi, mwando wevhu unogona kuratidzwa ne chiyero chemwando Sr chinomirira chiyero chehuremu chaihwo hwemvura iri muvhu kune huremu hwemvura iri muvhu iroro kana mhango dzose dzaive dzazadzwa nemvura, kureva kuti, kune huremu hwemvura yevhu rakazara nemvura:
zvichireva kuti kune _γ_w = 1,00 Sr = w*γs / e.
Miganho yemwero weunyoro ndeiyi:
- nokuda kwevhu rakaoma chose w = 0; Sr = 0
- kune ivhu rakazara zvizere nekunyorova w = e/γs; Sr = e/γs * γs / e = 1,0.
Sl. 6. Muenzaniso wevhu wakazara nemvura zvishoma
Mwero wekuzara (unonzi dzimwe nguva zvakare kuzara kana mwero wehunyorova) unoratidzwawo nehukama hwevhoriyamu yemapores akazadzwa nemvura kuenda kuvhoriyamu yakazara yemapores (muf. 6):
Sr = V2 / V1
apo V2 iri vhoriyamu yemaporo akazadzwa nemvura, V1 iri vhoriyamu yose yemaporo akazadzwa nemvura, mhepo nemagasi. Kana w iri hunyoro hwevhu mu% yehuremu hwakaoma hwevhu Wd, zvino tine
V2 * γW = w Wd, kubva ipapo V2 = w Wd / γw.
Kune rimwe divi, tine kuti V1 = V – Vd, uye sezvo Vd * γs = Wd, zvino
Vd = Wd / γs uye V1 = V – Wd / γs.
Saka, dhigirii rekuzara kwevhu Sr richava
kana muzana wehuremu hwakaoma hwetsoili
Ivhu rakaoma chose
Muchiitiko ichi w = 0. Mvura yose iri mumaporo yabviswa, ukuwo mvura yakamonyororwa yakabviswa zvishoma chete, kureva kuti firimu remvura richiripo, asi ukobvu hwaro hwaderedzwa.