Kwanciyar gangar jikin ƙasa

** Abubuwan ƙwararrun ƙwararrun kayan tarihi da haɗari mai haɗari:** labarin yana adana tarihin kwanciyar hankali, alamomi, dabaru da zane-zane daga ainihin rubutu. Ba binciken kimiyyar ƙasa ba ne, tonowa ko aikin ƙwanƙwasa, lissafin kwanciyar hankali, shirin magudanar ruwa, tantance zaizayar ƙasa ko umarnin aiki. Wani gangaren da ba shi da kwanciyar hankali zai iya binne mutane ba zato ba tsammani, gine-gine da hanyoyi; ya kamata a kula da tsagewar gani, kumburi, ruwan gajimare, kwatsam ko ƙaura a matsayin dalili na ƙaura daga yankin haɗari da ƙima na ƙwararrun gaggawa.

A yau, Savo Kusić yana mai da hankali kan gilashin katako, itace-aluminum Taga, Taga na al’ada, kofa da buƙatun magana. Wannan labarin ya ci gaba da kasancewa a matsayin tarihin fasaha kuma baya wakiltar tayin ƙirar ƙirar ƙasa, kulawa ko aiwatar da ayyukan ƙasa.

Dangane da abubuwan da aka gina na ƙasa kamar yankewa, tarkace da magudanar ruwa, tsaunin ƙarshe yakan rushe wani lokaci. Kuma gangaren dabi’a, ba tare da ayyukan wucin gadi ba, na iya motsawa ba zato ba tsammani kuma da ƙarfi sosai ko a hankali. Wadannan al’amura sun dade da zama batun nazarin ilimin geological da geomechanical, tare da manufar kimanta kwanciyar hankali daga halayen jiki na ƙasa da yanayin kowane lamari.

Dalilan motsin talakawan duniya

Sharadi na zaman lafiyar kowace kasa, ko dai wani abu ne na kasa na wucin gadi ko kasa na halitta, shi ne cewa akwai daidaito tsakanin dakarun waje da juriya na cikin kasa. Sojojin waje sune farkon nauyin ƙasa, wanda yawanci shine kawai ƙarfin waje, sannan kuma duk wani nauyin waje wanda ke aiki akan gangara, dindindin ko motsi. Juriya na ciki ya ƙunshi haɗin kai da gogayya a cikin ƙasa da aka daure, kuma kawai gogayya a cikin ƙasa mara ɗaure.

Sl.1. Spep of lese ground embankment

Idan muka lura da wani shinge mai tsayi h da aka yi da ƙasa maras kyau, misali busasshen yashi, za mu tantance cewa gangaren wannan ginin yana karkata a kusurwa β zuwa kwance (fig.1). Girman kusurwar β ya dogara da abubuwa da yawa kamar girman hatsi, siffar hatsi da ƙaddamarwa. Idan muka ƙara tsayin h zuwa h1, h2 da dai sauransu tare da kayan da ba a ɗaure guda ɗaya ba na ƙaƙƙarfan ƙaƙƙarfan iri ɗaya, kusurwar β ba za ta canza ba, gangaren gangaren za ta kasance a gangare ɗaya har zuwa tsayi mara iyaka h. Don ƙasa maras kyau, kusurwar gangare ta halitta β ba ta da zaman kanta daga tsayin gangara h. Girman kusurwar β a cikin ƙasa maras kyau ya dogara da kusurwar juzu’in ƙasa na ciki φ kuma ana ɗauka ya zama ɗan ƙarami fiye da shi, ko daidai da shi, β ≤ φ.

Sl.2. Yanke gangare cikin daure kasa

Idan muka kalli yanke da aka yi a cikin ƙasa da aka daure, za mu ga cewa gangaren da aka yanke an ajiye shi a ƙarƙashin wani tudu mai ƙarfi.1: m, watau a babban kusurwa β saboda gaskiyar cewa juriya na ciki na ƙasa mai ɗaure yana ƙaruwa ta hanyar haɗin kai, wanda ba ya wanzu a cikin yashi bushe (fig.2). A cikin wasu nau’ikan ƙasa, irin su busassun loess, haɗin gwiwa na iya ƙara juriya na ciki har ta yadda za’a iya riƙe ƙasa tare da gefen yanke a tsaye, watau a kusurwa β =90°. Koyaya, idan muka ƙara tsayin yanke h a cikin ƙasa mai ɗaure zuwa h1, h2 da dai sauransu, dole ne a rage kusurwar karkatar da yanke β don kiyaye bevel cikin kwanciyar hankali. Ga kowane kusurwar gangare β na gangaren yanke a cikin ƙasa mai iyaka akwai tsayi ɗaya mai mahimmanci hc. Idan muka wuce wannan tsayin, gangaren AB ba za a kiyaye ta cikin ma’auni ba kuma zata zame akan wani wuri mai zamewa CD (fig.3). Zamewar ta faru ne saboda wani tashin hankali a cikin ma’auni tsakanin ƙarfin waje, nauyin kansa na nauyin ƙasa da kuma juriya na ciki, wanda bai isa ya yi tsayayya da karuwar ƙarfin waje ba, watau ga karuwar nauyin ƙasa wanda ya haifar da karuwa a tsayin gangaren h.

Sl.3. Spep of cut in cohesive ground

Daga abin da ke sama, ya biyo baya cewa kusurwar gangaren ƙasa na ƙasa ba za a iya ɗaukar shi azaman ƙima mai dorewa ga ƙasan da aka bayar ba, tunda ƙimarta a ƙarƙashin duk sauran yanayi ya dogara da tsayin gangaren kuma yana raguwa tare da haɓakar wannan tsayin. Duk da haka, ana ɗaukar shi sau da yawa don gangara na ƙananan tsayi a matsayin ƙima mai ɗorewa, ya dogara da kusurwar juzu’in ƙasa na ciki φ.

Har ila yau damuwa na ma’auni na iya faruwa ba tare da ƙara tsayin yanke ba h, misali lokacin da juriya na ciki na ƙasa ya ragu. Abubuwan da ke tattare da juriya na ciki na ƙasa da aka daure, haɗin kai da gogayya, suna da matukar canzawa kuma sun dogara da adadin ruwa a cikin ƙasa. Don haka, a lokuta da dama, dalilin zamewar shi ne yawan kasa da ke daure da ruwa, wanda zai iya yin girma ta yadda kasa ba za ta iya daukar kanta a karkashin kowane gangare ba, sai ta zame saboda nauyinta.

Sl.4. Zamewar ƙasa saboda samuwar filaye masu zamewa

Akwai lokuta daban-daban na zamewar ƙasa saboda raguwar juriya na ciki, waɗanda za mu ambata a nan kaɗan halaye.

Samuwar filaye masu zamiya

Idan akwai yumbu mai yuwuwar yumbu a kan gangara ƙarƙashin saman saman ƙasa na ƙasa mai lalacewa (Fig.4a), ko kuma idan akwai yashi mai karkata a cikin laka (fig.4b), wanda yanayin yanayi ko saman ruwa zai iya isa (misali daga ramin magudanar ruwa da aka yi watsi da su), filin na iya zamewa. Ruwan da ya fi girma yana wucewa ta cikin maɗauran raƙuman ruwa zuwa ɗigon yumbu, wanda yake jika sosai, yana rage juriya a saman, inda saman saman ya zame.

Rashin daidaituwa ta hanyar yanke yanke

Ta hanyar yanke yanke a lokacin gina layin dogo da tituna, yanayin da ya gabata na daidaitawa yana damuwa, saboda a cikin bayanin da aka yanke ƙasa ya kasance ba tare da tallafi ba kuma yana ƙoƙari ya koma ƙasa saboda nauyi. Ana iya kiyaye yanayin ma’auni idan juriya na cikin ƙasa ya yi girma isa don magance wannan hali, wanda kuma yana yiwuwa lokacin da ƙasa yanke ya ƙunshi yadudduka masu ƙarfi ga yanke.

Sl.5. Zazzagewar ƙasa saboda yankan ƙasa mai lallausan ƙasa

Duk da haka, idan an yanke yadudduka na ƙasa maras kyau da ƙasa mai lalacewa (fig.5), akwai yuwuwar zubewar ƙasa mai raɗaɗi da jika na ƙasa mara ƙarfi, wanda zamewar zai iya faruwa.

Rashin daidaituwar ƙasa

Ƙananan yadudduka na kayan da ba za a iya jurewa ba a cikin wani shinge da aka yi da ƙasa mai lalacewa, abin da ake kira. ruwan tabarau na yumbu (fig.6), Hakanan zai iya haifar da zamewa idan ruwa mai yawa ya isa gare su kuma ya samar da saman zamiya.

Sl.6. Al’amarin da ke zamewa saboda abubuwan da ba su dace ba

Tasirin sanyi

A ƙarƙashin rinjayar sanyi, ruwa yana taruwa a cikin saman Layer a cikin nau’i na ruwan tabarau na kankara. A lokacin narke, ruwan tabarau na kankara sun juya zuwa ruwa, wanda ya fi dacewa da ƙasa zuwa zurfin aikin sanyi, sakamakon haka ya zama ruwa mai yawa kuma ya rasa kwanciyar hankali.

Wannan yanayin yana faruwa ne kawai tare da ƙasa mai haɗari mai sanyi kuma tare da tsawon lokacin sanyi, saboda yana ɗaukar lokaci mai yawa don samuwar ruwan tabarau na kankara.

Rage matakin ruwan karkashin kasa

Lokacin da aka sauke matakin ruwan ƙasa na dindindin, misali saboda gudanar da aiki a cikin ƙasa, bushewar ƙasa yana faruwa kuma, idan yumbu ne wanda ke da babban kumburi, tsagewa suna bayyana. Ruwan sama da na yanayi yana shigar da su da yawa, yana yayyanka ƙasa da rage juriya na ciki, wanda kuma kan haifar da zabtarewar ƙasa.

Akwai wasu lokuta da yawa na zamewar ƙasa, don haka ana iya la’akari da cewa duk wani ƙasa mai daidaituwa zai iya, a wasu yanayi, ya rasa juriya na ciki zuwa babba ko ƙarami kuma, a ƙarƙashin rinjayar sojojin waje, a saita a cikin motsi.

Ƙasar da ba ta dace ba tana da kwanciyar hankali muddin kusurwar gangare ya yi ƙasa da kusurwar juzu’i na cikin ƙasa. Tare da irin wannan ƙasa, zamewa yana faruwa ne kawai idan kusurwar gangara ta fi girma fiye da kusurwar rikici na ciki. Duk da haka, idan an yi ƙugiya da kayan da ba a ɗaure ba a kan ƙasa mai yumbu, ƙasa mai yumbu na iya zamewa kuma ginin ya rushe, don haka wajibi ne a duba kwanciyar hankali.

Gwajin kwanciyar hankali na gangaren kasa

Siffar saman zamiya

Yanayin ma’auni tsakanin sojojin waje da juriyar ƙasa na ciki Coulomb ya saita shi tare da lissafinsa

τ ≤ c + σ tgϕ

inda τ shine damuwa na ƙasa, c shine haɗin kai, σ shine damuwa na yau da kullun akan saman zamewa, ϕ shine kusurwar gogayya ta ciki.

Idan juriyar cikin ƙasa, haɗin kai c da gogayya σ tgϕ ba su wadatar don adawa da matsananciyar ƙarfi na ƙasa ba, zamewar na faruwa a saman zamiya a cikin ƙasa. Akwai nau’o’i daban-daban na shimfidar zamewa, wanda ya dogara da kaddarorin jiki na ƙasa, shimfidawa, zafi, nauyin waje da sauran dalilai.

Dangane da matsayi, ana rarrabe al’amuran al’ada na zamewa:

Sl.7. Al’amuran zaizayar kasa

a) Zamewar ɓangarorin a tsaye na yanke. A cikin yanayin tashoshi don samar da ruwa, magudanar ruwa, da sauransu, waɗanda aka haƙa tare da bangarorin tsaye (fig.7a), idan mahimmin tsayin hc, wanda ya dogara da kayan aikin ƙasa, ya wuce, zamewa a saman ADC yana faruwa. Wadannan nunin faifai yawanci ba su kasance tare da duk tsawon tashar ba, amma an yi su ne a cikin gida, wanda aka bayyana ta rashin daidaituwar ƙarfin ƙasa.

b) Babban gangaren gangare (fig.7b). Wadannan zamewar sau da yawa suna bayyana a cikin bazara a kan yankan hanyoyin layin dogo da hanyoyi kuma sakamakon oversaturation na ƙasa da ruwa.

c) Mai zamewa da ƙafafu (fig.7c). Shi ne zamewar gaba dayan gangaren da aka yanke ko damtse zuwa kafar C.

d) Slope zamewa a gindin kafar (fig.7d). Shi ne zamewar dukan gangaren yanke ko shinge da ƙasa a ƙarƙashin ƙafa. Wannan zamewar kuma ana kiranta karayar ƙasa ko kuma karaya ta Sweden, bayan mutanen Sweden waɗanda suka fara bayyana shi.

Dangane da siffar shimfidar wuri, za a iya cewa kawai zamewar saman ƙasa a cikin ƙasa mai haɗin gwiwa ba madaidaiciyar ƙasa ba ce, a maimakon haka saman mai lanƙwasa ne. Wasu mawallafa sun ɗauki baka mai madauwari (Fellenius), karkace na logarithmic (Rendulić) ko haɗin waɗannan layukan lanƙwasa (Brinch Hansen) azaman siffar saman zamiya.

Tasirin tace ruwa akan kwanciyar hankali

Idan akwai ruwa na waje a gaban gangaren tare da matakin N1(fig.8), Ruwan ruwa yana faruwa a cikin ƙasa a bayan gangaren, wanda ke haifar da matsa lamba na ciki a cikin pores, sakamakon abin da rikici tsakanin ƙwararrun ƙwayoyin cuta ya ragu kuma damuwa a cikin ƙasa yana ƙaruwa.

Idan matakin shine N1 Ruwan da ke gaban gangara akai-akai, ginshiƙin ruwa H *γW yana haifar da matsewar ruwa a cikin ramukan ƙasa, wanda ke rage juzu’in da ke tsakanin tsattsauran ɓangarorin, sakamakon haɗarin zamewar gangara. Koyaya, lokacin da matakin shine N1 akai-akai, matsawar ginshiƙin ruwa H*γW yana tura ƙwaƙƙwaran ɓangarorin zuwa cikin ƙasa, saboda haka haɗarin zamewar gangara ya ragu zuwa wani wuri. A wannan yanayin, a matakin ruwa akai-akai N1 a gaban gangaren akwai hatsarin zamewar gangaren gangaren, domin tasirin tace ruwa a cikin kasa yana haifar da tura tarkacen barbashi zuwa bangaren waje na gangaren gangaren.

Sl.8. Tasirin tacewa akan daidaiton gangaren kasa

Idan matakin ruwa na waje ya ragu sosai daga matakin _N1_na N2 to ana barazana ga zaman lafiyar gangaren sama. A wannan yanayin, ruwan rami na ciki yana gudana zuwa gefen waje na gangaren sama, yana tura daɗaɗɗen barbashi zuwa wancan gefen.

Saboda duk wannan, idan gangaren ƙasa ta nutse a cikin ruwa, ya kamata kuma a yi la’akari da tasirin tace ruwa yayin gwada daidaiton gangaren.

Tasirin tace ruwa a cikin ƙasa ya dogara da dalilai da yawa, mafi mahimmancin su shine permeability na ƙasa, hydrostatic matsa lamba na ruwa na waje, rate na raguwar matakin ruwa na waje da homogeneity na ƙasa.

Idan muka ɗauka cewa embankment a cikin fig.8na wani nau’in isotropic mai kama da juna, ƙarƙashin rinjayar matsi na hydrostatic na matakin ruwa na waje N1_Za’a samu magudanar ruwa a cikin rafukan katangar zuwa gangaren gangare, ta yadda ruwan karkashin kasa zai ragu tare da tsawon hanyar da aka bi. Idan muka gabatar da bututun piezometer AA’, BB’ da CC’ cikin tarkace (Fig.9), Ruwan ruwa a ƙarƙashin tasirin tasirin hydrostatic zai shiga waɗannan bututu kuma ya tashi zuwa matakin N1, wanda zai iya zama iri ɗaya a duk bututu, idan an zaɓi maki A, B da C don haka tsayin ginshiƙin ruwa a cikin bututu ya zama h1, h2 da h3.

Sl.9. Layin daidai da na yanzu

Idan muka yi alama da h tsayin matakin ruwa ya tashi N1dangane da wasu zaɓaɓɓun jirgin sama na O-O, to yuwuwar shine h ga kowa3maki, A, B da C iri daya. Layin da ke haɗa waɗannan maki uku shine equipotential line. Ruwan cikin ƙasa a cikin ƙasa ba zai iya gudana tare da wannan layin ba, amma a cikin hanyar maki tare da ƙananan yuwuwar.

Hakazalika, zamu iya zaɓar maki guda ɗaya D, E da  F tare da ƙaramin yuwuwar h ― Δh. Layin da ya haɗu da waɗannan maki uku shine madaidaicin layi na yuwuwar h ― Δh. Ruwa yana gudana daga aya A na layin equipotential ABC zuwa wani madaidaicin madaidaicin madaidaicin D na layin equipotential DEF zai kasance a cikin jagorar mafi girman hydraulic digo imax a cikin nisa. AD. Wannan yana nufin layin AD wanda ruwan ke tafiya tare da shi ya kasance daidai da layukan ma’auni guda biyu, domin shi ne.

imax = Δh / Δlmin

inda Δlmin ya zama al’ada ga duka layukan daidaitawa. Waɗancan ka’idodin daidaitattun layukan daidaiku sune hanyoyin tafiyar ruwa a cikin ma’aunin da ba za a iya jurewa ba kuma ana kiran su current Lines. Al’ummar layukan daidaitawa da na yanzu, masu ma’amala da juna, suna samar da hanyar sadarwa na igiyoyin ruwa.

Cibiyoyin sadarwa masu yawo suna da siffofi daban-daban bisa ga madaidaicin yawan jama’a. Shari’ar da aka fi sani da ita ita ce ginshiƙan da aka yi da taro mai yuwuwa akan ƙasa mara misaltuwa, watau a kan ƙasa wanda ba za a iya jurewa ba (Fig.10). A wannan yanayin, idan matakin ruwa na waje ya kasance akai-akai, raƙuman ruwa suna cikin tsakiyar ɓangaren su na parabola.

Sl.10. Tsarin hanyar sadarwa a cikin wani shinge mai yuwuwa akan ƙasa mara nauyi

A gangaren da ke sama, ana haɗa parabolas ɗin zuwa layin da ke daidai da gangaren, wanda ke wakiltar layin equipotential, saboda a koyaushe matakin N.1 ruwa baya gangarowa gangare. Tare da gangaren gangaren ƙasa, parabolas ɗin suna ƙarewa a hankali zuwa gangaren, wanda ba layi bane mai ƙarfi ko layin yanzu. Fuskar ƙasa mara kyau da ke ƙasa da ƙwanƙwasa yana da sauƙi, saboda ruwan da ke ƙasan ginin yana gudana daidai da wannan saman. A cikin ɓangaren sama, cibiyar sadarwa mai gudana ta ƙare da ainihin parabola mai suna seepage line, wanda ke wakiltar iyakar ƙasa ƙarƙashin aikin tacewa. A ƙasan wannan iyaka, ƙasa tana ƙarƙashin tasirin tacewa saboda matsa lamba na ruwa na waje H \ * γW, yayin da babu tacewa a cikin ƙasa sama da shi. Ana kuma kiran layin saturation, tun da ana ɗauka cewa ƙasan da ke ƙarƙashinsa ta cika da ruwa, yayin da sama da shi ya cika.

Ƙimar gangare na gaske dole ne ya haɗa da bincike, ƙididdigewa, sigogin ƙarfi, ruwan ƙasa da ruwan saman ƙasa, sauye-sauyen matakin, magudanar ruwa, girgizar ƙasa, matakan tono ko cikowa, tsarin da ke kusa, da yanayin wucin gadi. Hakowa ba tare da kariyar da ta dace ba da shigar da yankin yiwuwar zabtarewar ƙasa ba shi da aminci bisa ga rubutu na gaba ɗaya ko siffar gangaren kanta.