Te hanganga o te oneone
Ko te hanganga o te oneone ko te whakaraupapatanga o te wāhanga mārō i roto i te papatipu whenua. E mōhiotia ana, he mea hanga te oneone i ngā matūriki mārō me ngā kōhao kua whakakīa ki te wai, ki te hau, ki te korohū wai rānei, i te nuinga o te wā he wāhanga hau, he wāhanga wai. E ai ki te whakaraupapatanga o ngā matūriki mārō i te oneone ka tautuhia tōna hanganga. He tino rerekē ngā hanganga o te oneone kāore i herea me te oneone herea i a rāua anō.
Hanganga o te oneone kāore i herea
Ka puta te hanganga o te oneone kore here i raro i te pānga o te tō. He nunui ake ngā matūriki mārō o tēnei oneone, ā, ka taka whakararo, ka tōpū i raro i te pānga o te tō, i te mea kāore, he iti rānei, ngā kaha kukume i waenga i ngā rāpoi ngota o aua matūriki, ā, ka wikitoria e te tō. Nā reira, i te oneone kore here ka tū ngā matūriki mārō ki te taha o tētahi ki tētahi, ka noho ki te wāhi wātea i waenga i ngā matūriki kua whakaraupapatia (wh. 1_a_). Mēnā he āhua porowhita tata ngā matūriki o te oneone kore here, ā, he ōrite te rahi, pēnei pea i te onepu o te hanganga ōrite, katahi ka tino mātotoru rawa te hanganga (wh. 1_b_) rānei tino nohinohi rawa (wh. 1_c_), e ai ki te whakaritenga o ngā matūriki mārō i roto i te oneone. E hāngai ana te hanganga tino mātotoru ki te tino nui rawa o te āhei kōpeke o te oneone kore here, ā, ko tōna kōataata ko nmin=26%. E hāngai ana te hanganga tino nohinohi ki te tino iti rawa o te āhei kōpeke o te oneone kore here, ā, ko tōna kōataata ko nmax=48%. Hei tauira, he n=47% tō te onepu wewete o ngā tāhuna.
Wh. 1 Te hanganga o te one kāore i herea
Mēnā he rerekē te kākano o te oneone kāore i herea, kia whakakī ai ngā matūriki pai ake i ngā kōhao i waenganui i ngā matūriki kākano nui ake (whak. 2), ka tino iti ake te kōputaputa o te oneone (n=20% me te iti iho).
Wh. 2. Te hanganga o te oneone kore here o ngā rahi kākano rerekē
Hanganga o te oneone here
I te oneone kua herea, he rerekē te hanganga i tō te oneone kāore e herea. I te oneone kua herea ka puta ngā kaha piringa, he kaha ake i te kaha tōmuri o ngā matūriki ririki, ā, ka whakapiri i a rātou ki ngā mata pā. Nā konei kāore ēnei matūriki e taka whakararo ā-rārangi, engari ka noho piri tonu tētahi ki tētahi me tētahi ki te taha o tētahi atu (whaka. 3_a_), ka hanga ai i tētahi hanganga rite ki te mekameka kupenga (whaka. 3_b_), he rite ki te kāhui huka (whaka. 3_c_) me ērā atu, e kīia ana he hanganga o te taumata teitei ake. He nui te porosity o ēnei hanganga, ā, ka tae ki te 60-80% o te papatipu katoa, kāore tēnei e taea i te oneone kāore e herea.
Wh. 3. Te hanganga o te oneone here
Porosity and porosity coefficient
Ka tautuhia te porosity o te oneone mā te ōwehenga o te rōrahi o ngā kōhao ki te rōrahi katoa o te oneone (wh. 4).
Whaka. 4. Te kōwaha me te taupū kōwaha o te one
Mēnā ka tohu mātou ki
- Vp = te rōrahi o ngā kōputaputa i te oneone
- Vm = te rōrahi o ngā matūriki mārō
- V = te rahinga katoa o te oneone,
Ko te porosity o te oneone n e ai ki te whakamārama
n = VP / V = VP / (VP + Vm),
arā rānei i te % o te rahinga katoa o te oneone
n = 100 * VP / (VP + Vm) %.
Ka tautuhia te tauwehe porosity o te oneone mā te ōwehenga o te rōrahi o ngā pore ki te rōrahi o ngā matūriki mārō:
e = VP / Vm.
Mai i te tauira mō te pūporosity n ka whiwhi tātou:
nVP + nVm = VP, nā reira Vm = VP(1-n) / n.
Mā te whakakapi i tēnei uara ki te tauira mō e ka whiwhi tātou
e = n / (1-n).
Mai i tēnei whārite ka whiwhi tātou
e - ne = n; n = e / (1 + e).
E whakaatu ana te taupū kōputaputa i te mātotoru o te oneone. Mēnā he nui ake te taupū e, ka iti ake te mātotoru o te oneone, ā, he pēnei anō te ritenga. Ki te taupokihia tētahi oneone kōpeke i raro i te kawenga, mā te taupū kōputaputa i mua i muri hoki i te tāngatanga ka taea te whakatau te rahi o te tāngatanga Δ_h_.
Whakaarotia tētahi paparanga oneone kōpī, he h te matotoru (wh. 5_a_). Mēnā ka utaina tēnei paparanga, ka noho ki raro mā te teitei Δ_h, nō reira ka heke tōna matotoru nā te kawenga ki h1. Nō reira
Δ_h_ = h – h1.
I te mea ka mahia te noho iho o te oneone kōpeke i runga i ngā kōhao, nō te mea he tata kore e kōpeke ngā matūriki mārō, ā, me te wai anō hoki, mēnā kua whakakīa ngā kōhao o te oneone e taua wai i te wāhanga, i te katoa rānei, ka taea tēnei noho iho te whakaatu ā-ataata i te āhua 5_b_.
Whakaahua 5. Ko te nohoanga Δh o tētahi paparanga oneone kōpeke te matotoru h i raro i te utanga
Ki te tohu tātou i te teitei pohewa h0 o te paparanga matūriki mārō kāore he kōhao, e kīia nei ko te teitei whakaheke, ka taea te whakapuaki i te tūtukitanga Δ_h_ ki te teitei whakaheke h0 mā te hononga:
Ki te whakaarohia he paparanga oneone he ōrite te whānui me te roa ki te kotahi, ka tū ngā teitei h, h1 me h0 hei rōrahi, nā reira ko
i reira ko e te taupū kōwhao i mua, ko e1 i muri i te tītīhanga. Mai i te mea o mua ka whiwhi te tītīhanga
Δ_h_ = h0 (e-e1).
Ka taea te whakaatu te tōpata hei ōwehenga ki te teitei o te paparanga h i mua i te tōpata mēnā ka whakakapi tātou i te uara o te teitei whakaitihia h0:
h0 = h – nh = h (1-n) = h / (1+e),
i te mea ko n = VP / V = VP / h_,_ nā reira ko VP = nh.
Nā reira ka whiwhi
He pēnei ngā uara toharite o te porosity n me te āhuatanga porosity e mō ētahi momo oneone:
Haumākū o te oneone
Ngā momo wai i te oneone
Ka puta te wai i roto i te oneone hei wai i ngā kōhao i waenga i ngā matūriki mārō, arā ko te wai kōhao, kātahi hei wai adsorbovana i runga i ngā matūriki mārō, ā, hei wai hanganga.
Ko te wai pore he mea tito ki te wai herekore i waenga i ngā matūriki mārō, ā, ka neke mā runga i te ture a Darcy, kātahi ko te wai tōnekeneke, e neke ana i raro i te awe o te tōpana mai i runga ki raro i ngā ahunga katoa, engari kāore tōna nekehanga e rite ki te ture a Darcy, te wai kapira e neke ana i raro i te awe o ngā kaha kapira, me te wai o te taumahatanga mata, e pupuri ana e te taumahatanga mata i ngā kokonga i waenga i ngā matūriki mārō o te oneone, ā, e kīia anō ana ko te wai pore koki. Ka taea te tango katoatia i tēnei wai mā te whakamaroke i te oneone i te pāmahana o 110oC.
Ko te wai adsorbovana te wai e tāwharau ana i ngā matūriki mārō, ā, e herea ana ki a rātou e ngā kaha rāpoi. Koinei te mea e kīia ana ko te kiri wai, ā, ko tōna matotoru e neke ana 6-80 µµ (1µµ=10-6 mm, milimikron). He iti noa te pānga o te wai adsorbovana ki ngā matūriki nui ake; heoi, ka iti ake ngā matūriki, ka nui ake tōna pānga, nā te mea ka piki te mata whānui o ngā matūriki, ā, nā reira hoki te ōwehenga o te wai adsorbovana ki ngā matūriki mārō i roto i te rōrahi kotahi o te oneone. Ka taea tēnei wai te tango wāhanga noa mā te whakamaroke ki te 110oC.
Ko te wai hanganga he wai kua hono matū ki roto i ngā karaihe o ngā kohuke o ngā matūriki mārō o te oneone. He tino iti noa tēnei wai, ā, kāore e taea te tango mā te whakamaroke i te oneone. Nō reira ka taea te whakaaro he wāhanga tūturu nō te matūriki mārō.
Te nui o te wai i roto i te oneone
E ai ki te whakamāramatanga, ko te nui o te wai i roto i te oneone, arā ko te makuku o te oneone, ko te ōwehenga i waenga i te taumaha o te wai kei roto i te oneone me te taumaha o ōna wāhanga mārō. E ai ki te nui o te wai i roto i te oneone ka wehea ki ngā take e toru: he oneone kua tino kī i te wai, he oneone kua kī wāhanga i te wai, ā, he oneone tino maroke.
He oneone kua kī katoa i te wai
Mēnā ka tohu tātou i te n mō te kōwawatanga o te oneone, γs mō te taumaha rōrahi o ngā matūriki katoa, γw mō te taumaha rōrahi o te wai, ka taea te whakaatu i te haumākū o te oneone kī tonu wZ mā te whārite e whai ake nei
He oneone kua tino kī ki te wai
Ki te tohu tātou i Ww hei taumaha o te wai kei roto i te oneone, ā, Wd hei taumaha o ngā matūriki mārō, arā, te taumaha maroke o te oneone, nō reira ko te haumākū o te oneone w
w = Ww / Wd , arā, i ngā ōrau o te taumaha maroke o te oneone: w = 100 Ww / Wd.
I tēnei take ka taea te whakaatu i te makuku o te oneone mā te taumata makuku Sr e tohu ana i te ōwehenga o te taumaha tūturu o te wai i roto i te oneone ki te taumaha o taua wai anō i taua oneone mēnā ka whakakiia katoatia ngā kōhao katoa e te wai, arā rānei, ki te taumaha o te wai o te oneone kua kī i te wai:
or for _γ_w = 1,00 Sr = w*γs / e.
Ko ngā uara pae mō te taumata makuku ko ēnei:
- mō te oneone maroke rawa w = 0; Sr = 0
- mō te oneone kua tino kīa w = e/γs; Sr = e/γs * γs / e = 1,0.
Fig. 6. Soil sample partially saturated with water
Ko te taumata kukū (i ētahi wā ka kīia anō ko te kukūtanga, ko te taumata haumākū rānei) ka whakaaturia hoki hei ōwehenga o te rōrahi o ngā kōhao kua whakakiia ki te wai ki te rōrahi katoa o ngā kōhao (whakaahua 6):
Sr = V2 / V1
kei reira ko V2 te rōrahi o ngā kōputaputa kua whakakiia ki te wai, ko V1 te rōrahi katoa o ngā kōputaputa kua whakakiia ki te wai, te hau me ngā kōhauhau. Mēnā ko w te makuku o te oneone i te % o te taumaha maroke o te oneone Wd, kātahi ka whai
V2 * γW = w Wd, nō reira ko V2 = w Wd / γw.
I tētahi atu taha, e mōhiotia ana ko V1 = V – Vd, ā, i te mea ko Vd * γs = Wd, koia nei
Vd = Wd / γs me V1 = V – Wd / γs.
Nō reira, ko te taumata whakakī o te oneone Sr ka
arā, i roto i ngā ōrau o te taumaha maroke o te oneone
He tino maroke te oneone
I tēnei take ko w = 0. Kua tangohia katoatia te wai kōputaputa, engari kua tangohia āhua noa iho te wai kua ūhia ki te mata, arā, kei te noho tonu te kiriata wai, engari kua iti ake tōna mātotoru.