Iinguqu zomhlaba ngenxa yesenzo seqhwa
Xa kufika iqabaka, amanzi akhululekileyo angahambiyo aba ngumkhenkce kwi-0°C yaye ngaloo ndlela ande ngo-9% wobungakanani bawo. Nangona kunjalo, amanzi akwiityhubhu ezincinci ze-capillary awaqhwi kwi-0°C, koko emahlukhuni asezantsi, asusela ku–1°C ukuya ku–78°C. Obu bushushu bokugqibela bokukhenkceka buqinisekiswe ziimvavanyo zaselebhu eMelika. Ukuba ityhubhu ye-capillary incinane ngakumbi, ubushushu bokukhenkceka buba sezantsi ngakumbi.
Emhlabeni kukho iipore ezidityaniswe omnye komnye kuzo zonke iindlela zibe yimisele ye-capillary. Esantini iipore zinkulu zize zenze imisele ye-capillary ebanzi, apho amanzi ekhenkcelela khona kwi-0°C okanye kubushushu obuncinane kancinci. Amanzi ekhenkcelela ngokulinganayo, apho kwiipore kuveliswa iikristale zomkhenkce, ukwanda kwazo ngomthamo nge-9% kungabangeli naluphi na utshintsho olukhulu emhlabeni. Kumhlaba oneenkozo ezincinci iipore zincinci zize zenze imisele ye-capillary emxinwa apho amanzi ekhenkcelela kubushushu obungaphantsi kwe-0°C. Noko ke, kumaleko angaphezulu umhlaba uhlala ukhululekile ngakumbi uneepore ezinkulu, apho amanzi ekhenkcelela khona kwi-0°C aze enze iikristale zomkhenkce. Ezi kristale zitsalela kubo amanzi apholiswe kakhulu avela kwiipore ezimxinwa ngamandla amakhulu, okubizwa ngokuba ngamandla okwenza iikristale. Xa amanzi anjalo atsalelwe kufika ekunxibelelaneni neekristale zomkhenkce kwaye nawo ekhenkcelele, anyusa umthamo weekristale zomkhenkce, eziba ziilensi zomkhenkce, ubukhulu bazo obunokuba malunga ne-0,1 ukuya ku-10 mm. Iilensi zomkhenkce ezibunjiweyo zibangela ukuguquka okukhulu komhlaba ngexesha lesenzo somkhenkce, nto leyo phantsi kweemeko ezimbi kakhulu enokufikelela ku-30 no-50 cm.
Ukuvela kunye nobukhulu bokonakala komhlaba ngenxa yesenzo seqhwa kuxhomekeke ikakhulu kwezi 3 zinto zilandelayo:
-
Umgangatho wamanzi angaphantsi komhlaba
-
Ixesha lokuhlala kweqabaka.
Ad 1) Ngokumalunga nolwakhiwo lweenkozo, eyona mpembelelo inkulu yeqabaka ikumhlaba oneenkozo ezincinane, onemingxuma emincinci ngokwaneleyo ukwenza imibhobho emxinwa ye-capillary, yaye ngaxeshanye unokungena ngokwaneleyo, nto leyo evumela ukujikeleza ngokukhawuleza kwamanzi ngexesha leqabaka. Olo hlobo lomhlaba lolona lubuthathaka kakhulu kwiqabaka, ngokwexesha lokuvela kwayo nangokobukhulu bokuguquka. Loo yimihlaba enothuli, equlunqwe ikakhulu ziinkozo ezinobukhulu be 0,02-0,002 mm. Iinkozo ezinobukhulu >0,02 mm zinobude obuncinane bokunyuka kwe-capillary, ngoxa iinkozo ezinobukhulu < 0,002 mm zinokunyuka kwe-capillary okucothayo, ukuze kuzo zombini iimeko ngexesha leqabaka kufike kuphela inani elincinane lamanzi kummandla wesenzo seqabaka. Ukuba umhlaba wodongwe une 25% yamasuntswana anobukhulu < 0,002 mm, ukungena kwamanzi emhlabeni kuncinane kakhulu yaye ukujikeleza kwamanzi kwimigodi kucotha kangangokuba kuloo mingxuma amanzi aqala abe ngumkhenkce ngaphambi kokuba iilensi zomkhenkce zitsalwe.
Ad 2) Ukongeza kwiimeko eziphathelele ukwakheka kweenkozo zomhlaba kufuneka kuhlangatyezwane nenye imeko ukuze kuvele ukuguquka komhlaba ngenxa yekhephu. Yiyo leyo yokuba kubekho ithuba lokunikela amanzi kummandla wesenzo sekhephu. Ukuba le meko ibingazalisekanga, oko kukuthi ukuba iikapilarhi zomhlaba bezingadibani namanzi aya kuhlala ehamba kuzo ngexesha lokusebenza kwekhephu, akuyi kubakho kuguquka ngenxa yekhephu, kungakhathaliseki nokuba loluphi na ulwakhiwo lweenkozo zomhlaba.
Okukhona umgangatho wamanzi aphantsi komhlaba uphezulu, kokukhona ithuba lokuguquka komhlaba ngenxa yesenzo seqabaka likhulu. Ukuba umgangatho wamanzi aphantsi komhlaba usekho kubunzulu obukhulu kunobude bokunyuka kwe-capillary kwamanzi aloo mhlaba, ukuguquka okubangelwa sisichotho seqabaka kuncinane kakhulu.
Ad 3) Ukuba ixesha lemveliso eqhubekayo yekhephu lide, kokukhona ukuguquka okubangelwa likhephu kuba kukhulu, ngenxa yokwenziwa kweelensi ezinkulu nezininzi. Ikhephu elinamandla nelifutshane libangela ukuguquka okuncinci, kuba kule meko amanzi emingxunyeni angqeleka ngesiquphe yaye ukuhamba kwawo kwekapilari kuyaphazamiseka. Ngokuchaseneyo, ikhephu eliphakathi nelide libangela ukuguquka okukhulu ngenxa yokwenziwa ngokungathintelwa kweelensi zomkhenkce.
Impembelelo yokukhulula iinkomo ezibotshiweyo
Ngexesha lokunyibilika kweqabaka, kuqala kuyanyibilika iilensi zomkhenkce kwindawo ephezulu yomhlaba ongaphezulu, logama kanye ngezantsi kwayo kusala umaleko oqandisiweyo, ngoko ke nongangeneki. Njengoko iilensi zomkhenkce ezinyibilikileyo zinika isixa esikhulu samanzi, esingenako ukungena kumaleko asezantsi aqandisiweyo, esi sixa sonyukileyo samanzi kumaleko ongaphezulu sisalisa umhlaba ngamanzi de ugcwale kakhulu kwaye uwujike ube bubunzima bolwelo, olungenawo nawuphi na amandla, koko lukhutshelwa ecaleni phantsi koxinzelelo. Iinguqu zomhlaba ngenxa yesenzo sokunyibilika kweqabaka zinokuba zinkulu yaye kwezinye iimeko zibe yingozi. Ezi nguqu zixhaphakile kwizisele ezikwiindlela zikaloliwe nasezindleleni, apho entwasahlobo kusenzeka ukutyibilika kwenxalenye yamathambeka ngenxa yokuzaliseka komhlaba ngamanzi avela kwiilensi zomkhenkce ezinyibilikileyo, kwakunye nasezindleleni, apho imiphezulu yendlela iguquka phantsi kwetrafikhi kumhlaba ophulukene namandla okuthwala ngenxa yokuzaliseka ngamanzi.
Ikhrayitheriya yokuvavanya impembelelo yeqabaka emhlabeni
Ngokufunda impembelelo yeqabaka kwiintlobo ngeentlobo zomhlaba kuye kwafikelelwa kwisigqibo sokuba, ngokwempatho xa kufeze iqabaka, kufuneka kwahlulwe iintlobo ezimbini zomhlaba: ezikhuselekileyo nezisengozini yeqabaka.
Imihlaba ekhuselekileyo kwiqabaka yileyo, apho kungaveliswa iilens zomkhenkce, nokuba ixesha leqabaka lide kangakanani. Kolu hlobo lomhlaba kukho kuphela ukubanda kwamanzi asezimbotsheni zalo kunye nokwakheka kweekristale zomkhenkce, okunokuguquka okuncinane xa iqabaka isebenza. Kule qela kungena igrabile, isanti nemihlaba efana nayo.
Imihlaba eyingozi ngenxa yebhanti yeqabaka yileyo apho kuveliswa iilensi zomkhenkce, ngenxa yoko kunokuvela iiguquko ezinkulu. Amanzi aqokelelene kumaleko angaphezulu ngohlobo lweelensi zomkhenkce ngexesha lokusebenza kweqabaka nawo avelisa isiphumo sokunyibilika komhlaba. Kule qela kungena imihlaba ethile enothuli-nodongwe, ngakumbi imihlaba enothuli._
Kukho imilinganiselo emininzi yokuvavanya ukuzinza komhlaba ekubandeni, phakathi kwayo eyaziwa kakhulu yimilinganiselo kaArthur Casagrande noRuklia, esiza kuyichaza apha.
Umgaqo A. Casagrande
Le migaqo isekelwe kubume be-granulometric bomhlaba kwaye ithi:
a) Kwimihlaba enesakhiwo esifanayo, apho inqanaba lokungalingani U < 5, umhlaba usengozini kwingqele ukuba uqulethe ngaphezu kwe 10% yeemvuza ezinobukhulu obungaphantsi kwe 0,02 mm.
b) Kwimihlaba enobume obungalinganiyo, enobungakanani bokungalingani U > 15, umhlaba uba sesichengeni seqabaka ukuba uqulethe ngaphezu kwe3% yeenkozo ezikumgangatho ongaphantsi kwe0,02 mm.
Nangona lo mgaqo usetyenziswe ixesha elide yaye uhlala unika iziphumo ezithembekileyo, isiphene sawo kukuba usekelwe kuphela kumlinganiselo wegranuli yomhlaba yaye awuthatheli ngqalelo nezinye izinto ezinempembelelo kwintsebenzo yeqabaka emhlabeni. Ngenxa yoko, namhlanje kucingwa ukuba lo mgaqo ungqongqo kakhulu kwaye awunabungqongqo kwezoqoqosho.
Umgaqo kaRukliev
Ngale ndlela umhlaba wahlulwa ube zii-frakshini ezimbini ngokobulukhuni bamasuntswana aqinileyo, oko kukuthi kwifraksioni enamasuntswana amakhulu, amasuntswana anobubanzi d > 2 mm kunye nefraksioni enamasuntswana amancinci, amasuntswana anobubanzi d < 2 mm. Ukuvavanya ukumelana komhlaba kwikhephu, kumiselwa ubudlelwane phakathi kwesixa sefraksioni enamasuntswana amancinci kunye nesixa sefraksioni enamasuntswana amakhulu, yaye olu budlelwane lunikwa ngumda osezantsi nowongasentla (sl. 1).
Umda osezantsi umele ipesenti ephezulu evumelekileyo yamasuntswana aqinileyo anobubanzi d < 0,02 mm yobunzima obomileyo bokugcwaliswa, oko kukuthi iqela lama 0-2 mm, apho phantse kungabikho monakalo ngenxa yeqabaka phantsi kweemeko ezingathandekiyo, ezifana nenqanaba eliphezulu lamanzi aphantsi komhlaba, iimeko zemozulu ezingathandekiyo (iintsholongwane zeqabaka ezihlala ixesha elide) kunye nokufuma okukhulu kwendalo komhlaba.
Umda ophezulu umele ipesenti enkulu evumelekileyo yamasuntswana d < 0,02 mm zobunzima obomileyo becandelo elinamasuntswana amahle, apho phantsi kweemeko ezilungileyo, ezinjengeqondo eliphantsi lamanzi angaphantsi komhlaba, iimeko zemozulu ezilungileyo (iqabaka yexesha elifutshane) kunye nokufuma okuphantsi kwendalo komhlaba, phantse akukho monakalo uvela ngenxa yeqabaka.
Umz. 1 Umda osezantsi nowangaphezulu wokuvavanya ingozi yomhlaba ekubandeni ngokomgaqo kaRukliew
Ukhuseleko kwimiphumo yeqabaka emhlabeni
Ubunzulu bempembelelo yeqabaka emhlabeni buxhomekeke kwiimeko zemozulu zommandla. Kwilizwe lethu busoloko bungena 0,8 ukuya ku 1,0 m phantsi komhlaba. Ngoko ke, izakhiwo ezisisiseko ezikubunzulu obulingana okanye obungaphezulu kwe 1,0 m aziyi kuchaphazeleka likabaka.
Izakhiwo ezisungulwe kancinane ezifana neendawo zokuhamba kweemoto ezindleleni, zibonakaliswa yimpembelelo yekhephu, enokubangela iinguqu ezinkulu kunye nomonakalo kwindlela, kokubini xa kusiba ngumkhenkce naxa kunyibilika. Ngenxa yoko, xa kusenziwa iindlela kunye neendlela zokunduluka nezokuhlala kweenqwelo-moya kwiiaerodrome, kuyafuneka kuhlolwe umhlaba ngokubhekiselele kwimpembelelo yekhephu, yaye xa umhlaba wesiseko usengozini yekhephu, kufuneka kuthathwe amanyathelo okhuselo. Kwiindlela nasezindizeni ezisetyenziswa kwiiaerodrome elona nyathelo lisebenzayo kukwenziwa komaleko we-cushion, ubukhulu bawo bumiselwa ukuze ubukhulu obupheleleyo bendlela kunye nomaleko we-cushion bube 0,80 m kwizithuthi ezinzima ukuya kwi0,60 m kwizithuthi ezilula. Amaxesha amaninzi ubukhulu bomaleko we-cushion 0,30 m ngaphantsi kwendlela bunika ukhuseleko olwaneleyo ngokuchasene nempembelelo yekhephu.
Izinto ezisetyenziselwa ukwenza umaleko we-tampon ziqhele ukuba yisanti okanye igrabile enesanti, ekufuneka ihlangabezane nale miqathango ilandelayo:
Isalathisi seplastikhi IP < 5
Umxholo weqhekeza d < 0,02 mm ungaphantsi ko 3%
Iqondo lokungalingani U > 7.
Inxalenye ephezulu yomaleko we-cushion enobukhulu obuyi 20 cm akufuneki ibe sisanti efanayo nenenkozo entle ngenxa yokungabinaso isiqiniso esaneleyo kunye nomthamo wokuthwala onomda. Kule nxalenye, umaleko we-cushion kufuneka ube yigrabile enesanti ene 30-70% yamasuntswana anobukhulu 2-30 mm. Amasuntswana amakhulu kuno 30 mm awakhuthazwa.
Iindonga zocingo ezimiswe kancinane nazo zichaphazeleka yiqabaka emhlabeni, nto leyo ebangela ukuba zithambekele, ize le nto ngokuphindaphinda kwesenzo seqabaka ekuhambeni kwexesha ikhokelele ekuphendukeni nasekuweni kwazo. Ngenxa yoko ezi ndonga kufuneka zisekwe kubunzulu be 1,0 m, ukuba umhlaba usengozini yeqabaka.