Ntawm cov tiaj suabpuam thiab cov steppes uas nyob ib sab ntawm lawv, nyob rau ntawm lub roob toj siab, tsim ib hom av nplaum tshwj xeeb. Lawv hu ua loess thiab loess-zoo li loams. Nws yog ib qho qis-cohesive, yooj yim rubbed tsis-txheej pob zeb. Loesses feem ntau yog fawn-daj, fawn lossis lub teeb daj hauv cov xim. Loess zoo li loams - lub pob zeb uas tsis muaj cov yam ntxwv ntawm loess. Nws muaj porosity siab thiab calcium carbonate cov ntsiab lus.
Loess-zoo li loam: yam ntxwv
Raws li qee cov khoom thiab cov khoom siv granulometric, lub pob zeb mus txog mantle loams. Raws li txoj cai, loess tsis muaj cov xuab zeb loj dua 0.25 hli. Txawm li cas los xij, lub pob zeb no muaj cov hmoov av loj (0.05-0.01 hli). Nws cov ntsiab lus feem ntau ncav cuag 60-70%.
Lub pob zeb yog tus yam ntxwv ntawm cov txheej txheem tsis muaj zog, microaggregation, dej permeability siab. Loesses yog carbonate pob zeb. Hauv thaj chaw qhuav, lawv tuaj yeem ua ntsev thiab muaj gypsum hais.
Thawjtshwm sim los ntawm kev tawg ntawm loess-zoo li loams?
Lub pob zeb yog tus yam ntxwv ntawm macroporosity siab. Nyob rau hauv loess-zoo li loams, muaj kuj loj, ntsug tubules (pores) tshuav los ntawm cov hauv paus hniav tuag thiab stems ntawm cov nroj tsuag. Lawv qhov loj me yog qhov loj dua qhov loj ntawm cov kev suav nrog uas ua rau lub pob zeb. Cov tubules yog impregnated nrog txiv qaub, vim hais tias lawv tau txais ib lub zog. Tias yog vim li cas, thaum blurring, ntsug phab ntsa yog tsim. Thaum soaked, lub pob zeb muab ib tug loj drawdown vim muaj cov tubules, gypsum, carbonates, yooj yim soluble ntsev thiab colloids nyob rau hauv lub helium xeev. Qhov no ua rau loj deformations ntawm engineering lug.
Kwv Txhiaj Kwv Txhiaj
Tam sim no, tsis muaj kev pom zoo los ntawm qhov ua rau ntawm kev tsim cov loess-zoo li loams. Ntawm tag nrho cov kev xav uas twb muaj lawm, ib tus tuaj yeem paub qhov txawv ntawm eolian thiab dej-glacial. Thawj zaug tau thov los ntawm Academician Obruchev. Nws qhov kev xav tau ntxiv los ntawm Mirchinok, Arkhangelsky thiab lwm tus kws tshawb fawb. Raws li eolian hypothesis, loess-zoo li loams tau tsim los ntawm kev sib koom ua ke ntawm cov nroj tsuag, nag thiab cua.
Txoj kev xav glacial-dej txuas lub hauv paus chiv keeb ntawm lub pob zeb nrog cov xuab zeb tso los ntawm cov dej khov dej uas kis mus rau tag nrho saum npoo sab qab teb ntawm txoj kab glacial melting. Qhov kev xav no tau txhawb nqa los ntawm cov kws tshawb fawb xws li Dokuchaev, Glinka thiab lwm tus.
Txoj kev cawm seej
Nyob rau hauv cov qoob loo, loess-zoo li loams tsim pob tsuas. Nyob rau hauv cov cheeb tsam ntawm loess deposits, raws li ib tug txoj cai, tob ravines tshwm. Lawv ceev ceevnthuav dav mus rau sab thiab hauv qhov tob vim yog kev yaig ntawm phab ntsa los ntawm cov dej hauv av.
Integumentary loess-zoo li loams yog dav nyob rau sab hnub poob Siberia, nyob rau thaj tsam ntawm Uzbekistan, Kazakhstan thiab Tuam Tshoj.
Cov av tuab sib txawv ntawm qhov dav dav. Yog li, piv txwv li, nyob rau hauv Western Siberia nws yog nyob rau hauv 5,090 m, nyob rau hauv Central Asia mus txog 50 m los yog ntau tshaj. Hauv Suav teb, qhov tuab ntawm loess loams tuaj yeem ncav cuag 100 thiab txawm tias tshaj qhov nqi no.
Kev xaiv ntawm loess-zoo li loams yog muab rau hauv Interstate tus qauv GOST 21.302-96.
Siv txoj kev tsim kho
Loess-zoo li loams suav hais tias yog av tsis tsim nyog rau txoj kev tsim kho. Nyob rau lub caij qhuav lawv yog plua plav hnyav heev. Vim tsis muaj kev sib txuas ntawm kev sib xyaw ua ke, av abrasion tshwm sim, raws li qhov tshwm sim ntawm cov plua plav mus txog li ob peb kaum centimeters tshwm ntawm txoj kev. Lub sijhawm no hu ua "qhuav thaw". Thaum noo noo nkag mus rau hauv, cov av sai sai soaks, noj nyob rau hauv lub xeev kua. Nyob rau tib lub sijhawm, load kuj poob qis heev.
Ua ntej tso txoj hauv kev rau ntawm loess-zoo li loam, yuav tsum tau ntsuas tshwj xeeb los tiv thaiv txoj kab nqes yaig.
Nyiaj teb sib txawv
Loess-zoo li loams yog ntau coarse-grained thiab qis hauv carbonate. Carbonate loams pom nyob txhua qhov chaw ntawm qhov chaw tiaj tus uas tsis zoo nrog kev txhim kho me ntsis ntawm kev yaig network thiab ib qho me me ntawm cov hav dej.
SpatialQhov sib txawv ntawm loess-zoo li carbonate loams qhia lub sij hawm dependence ntawm av leaching ntawm cov degree ntawm lawv kev koom tes nyob rau hauv tus txheej txheem ntawm geomorphological txoj kev loj hlob vim lub ntuj tso dej ntawm qhov chaw. Qhov tsawg dua qhov chaw, qhov siab dua cov carbonate qab ntug hauv cov av profile.
Sporadic faib ntawm loess-zoo li carbonate loams nyob rau hauv lub strata ntawm carbonate-dawb pob zeb qhia qhov thib ob yam ntawm carbonization ntawm lub npog loamy massif nyob rau hauv arid tej yam kev mob. Lub xub ntiag ntawm massifs uas muaj cov carbonate loams qhia qhov ua tsis tiav ntawm lub voj voog geomorphological.
Mineralogical composition
Nyob rau hauv txhua loess-zoo li loams thiab European thiab Asian qhov chaw, nws zoo ib yam. Cov pob zeb muaj 50-70% quartz, 5-10% carbonate minerals, thiab 10-20% potassium-sodium feldspars.
Nyob rau hauv loess, ib qho tsis tseem ceeb ntawm cov zaub mov uas muaj hlau tau pom. Lawv cov concentration tsis tshaj 2-4.5%. Carbonate inclusions feem ntau pom nyob rau hauv silty feem. Lawv tau sawv cev los ntawm cov yeeb yaj kiab thiab cov khoom sib txuam hauv cov kab nrib pleb thiab qhov hws hauv daim ntawv ntawm impregnation.
Gypsum thiab silica tau tso ua ke nrog cov carbonate suav nrog. Raws li, av nplaum minerals, quartz, mica, feldspars, raws li zoo raws li dolomite thiab calcite muaj nyob rau hauv lub mineralogical muaj pes tsawg leeg, cov ntsiab lus ntawm uas yog ntau dua nyob rau hauv Central Esxias loess. Tsis tas li ntawd, cov ntsev yooj yim soluble thiab cov hlau hnyav (hauv qhov me me) tuaj yeem muaj nyob hauv cov khoom xyaw.
Ntaus loj faib
Nyob hauv cov pob zeb muaj cov ntsiab lus me me ntawm cov feem loj. Qhov nruab nrab, cov xuab zeb suav nrog rau 4.4% hauv loess, 11% hauv loess-zoo li loams. Cov ntsiab lus ntawm silt yog 5-35%. Nyob rau tib lub sijhawm, nws qib nce raws li cov av noo nce ntxiv thiab loess txav deb ntawm qhov chaw ntawm nws tsim.
Nyob rau thaj tsam ntawm Lavxias teb sab Plain, loess tau txais cov qauv clayey ntxiv los ntawm sab qaum teb mus rau sab qab teb. Ib tug txawv feature ntawm cov pob zeb yog ib tug loj npaum li cas ntawm coarse hmoov av. Nws qib nce mus txog 28-55%.
P. S
Loesses yog qhov txawv ntawm lawv cov peev txheej pauv cation tsawg. Qhov sib xyaw ntawm kev sib pauv cations muaj calcium thiab magnesium hauv qhov sib piv ntawm 3: 1, nrog rau sodium thiab potassium. Loesses yog tus cwj pwm los ntawm cov tshuaj tiv thaiv alkaline ntawm ib puag ncig.
Lub pob zeb muaj ntau yam khoom muaj txiaj ntsig zoo rau kev tsim av. Cov txheej txheem, tshwj xeeb, yog yooj yim los ntawm lub cev (siab noo noo, porosity, dej permeability), physicochemical thiab mechanical zog. Tsis tas li ntawd, lawv yog cov nplua nuj nyob rau hauv cov as-ham. Chernozem, grey hav zoov, txiv ntseej thiab lwm yam av fertile heev yog tsim los ntawm loess-zoo li carbonate loams thiab loesses.
High carbonate pab tsim cov humate-calcium humus. Nws kuj ua kom nws qhov xwm txheej zoo li qub thiab sib sau ua ke hauv cov nroj tsuag. Loesses muab cov av muaj txiaj ntsig zoo: nce carbonate cov ntsiab lus, microaggregation thiab porosity.
