KAWNG LEH LUNG

Lung hi hmanna a tam hle a, hmasawnna ruhrel hrang hrang zinga kawng siamnaah leh in saknaa kan hmanrua, rinrawl ber a ni. Lung hi thil sakhat a ni a, chu a sakhatna chuan mukna, chakna leh khawngna a neih avangin a ṭangkai hle. Cement concrete kan tih pawh hi a nihna takah chuan mihringte’n cement (binder), balu, rora leh tui chawhpawlh hmanga lung kan siamchawp (artificial rock) ti ila a sual tam lo ang.

Kawngpui hi lirthei rit tak tak tlanna a nih avangin chung rihna lo dolet tur chuan kawng ruhrel chak tha tak kan neih a ngai a. Thil rit tak lo dolet tur chuan kawng ruh, khawng ṭha leh chak tak kan siam a lo ngaih phah ta a ni. Tunlai thiamna sang zelah alkatra leh cement te lung nena chawhpawlhin kawng chhuatphah chung berah (wearing course) hman a lo ni ta zawk a. Kawngpui mam takah hahdam takin kan chuan theih phah a ni.

Lung insiam dan: Kan chenna leilung hi a insiam tirh chuan a sa em em a. Chung sa chu hun a lo rei fe hnuah an lo dai a, lung chang igneous rock-ah an lo chang ta a. Igneous rock te chu ni leh ruah hnathawh (weathering action) avangin an lo kehnawi leh a. Chung kehnawi te chu inchar khawm thei khawpa an lo indelh muk deuh deuh hnuin lungah an lo chang a, sedimentary rock tia sawi an ni. Sedimentary rock emaw igneous rock emaw te chu an lo indelh muk deuh deuh a, sa leh rihna nekna tha avangte chuan lung chang zawk a insiam leh te chu metamorphic rock tiin kan sawi leh a. Chung lung te chu a lo rei chuan nekna tha leh sa nasa lehzual avangin an lo tuiril a, magma tih an lo ni leh ṭhin. Magma te chu lei pawnah tlangkang ten an lo phuhchhuak leh ṭhin. Hetianga lung insiam kual dan hi lung inthlakkual (rock cycle) tih a ni.

Kan lung neih zawng zawng sedi­­mentary rock an ni a, chungte chu: Shale (lungkelha), Siltstone, Limestone (chinai lung), Sandstone leh Conglomerate te hi an ni. Lung hrang hrang hi hmun khatah a hlanga hmuh tur an tlem hle, an in awm pawlhin, an in bawh thuah (interlaminate/ interbed) tam ber zawk ṭhin.

Lung a hlanga an awmna hmun te chu quarry atana kan hman te hi an ni. Sandstone pawh hi shale leh siltstone nena awmkawpin hmun tam takah hmuh an ni. An lo in awm thuah ṭhin avang hian sandstone lung ṭha awmnaah pawh lung chang tawk lo clay/ silt/ shale te an lo awm ve ṭhin a, hriat hran loh chuan lung ṭha pangngai anga lak vek hi thil awl tak a ni.

Lung hrang inawmthuah chhan: Kan ram hi hun rei tawh takah khan tuifinriat hnuaiah a lo awm tawh ṭhin a. Tuifinriat chawmtu lui aṭanga lokal tui in a rawn ken tel lei nawi te chu, a zang apianga an tla har a, a rit apiang an tla hmasa ṭhin. Lei timur (grain size) lian deuh te chu an rih zawk avangin an tla hmasa a, hmun khata awm khawmin lung sandstone kan tih te hi a lo insiam a. Lei sin zawk, an zan avanga tla har te chu lo tla khawm ve leh in shale/ siltstone ah zawi zawiin an lo chang ve leh ṭhin. He kalphung hi a awm nawn (cycle) zel a, heng avang hian lung hrang hrang chu an lo in bawh thuah ta ṭhin a ni. Leinawi lo inchhek danah hian a rawn kengtu tuiluang leh tuifawn awm dan in kawngro a su hle.

Lung keh hma chhan: Kan ram lung te hi chang ṭha leh incharkhawm ṭha nei nual mah ila, kan lung tam zawk hi chu an inphuarkhawm ṭhat tawk loh avanga tuiin a chiah leh ni sain a em nasat deuha keh mai ṭhin an ni. Lung ṭhenkhat keh hma chhan chu an insiam dan phung avang te pawh a ni. Lung a tuizai (lamination) a tam viau chuan an sakhat lo a, rihna la em em lo pawhin weathering avangin an lo keh thei ṭhin. Tuizai kan tihah hian clay/ silt a awm ṭhin a, hengte hi lung ti chak lotute an ni. Tuizai inkar a zim viau phei chuan insakna leh kawngpui siamna atan hman a him lo. Hetiang lung keh hma (degradable rock) hi kan ngah avangin kan lung thlan kawngah leh kan hman danah pawh fimkhur a ngaih phah hle.

Rihna dolet thei lung: Kan lung tam zawk hi rihna tha pek miah lo pawh a zawi zawia keh sam an nih tehlul nen, a te zawkah kan han chhu keh leh a. Roller-in an chilmuk hnu leh lirthei ten an han rah hnu ah Indian Road Congress (IRC) specification-in a sawi lung size dik thlap a kan hman kha kum reilote ah an lo keh avangin a lenzawng (size) a dik lo ta vek ṭhin. Kawng ruhrel chhunga tui inpaihna tur (sub-surface drainage) pawh hnawhping thei khawpa kar awl awm lo in an lo muk telh telh ṭhin.

Kawng siam kalphungah hian, lungpui pawh lungtein a kamki loh chuan a awm thei lo tih ang khan, lung lian leh lung te tha taka inkamki a, rihna lokal rual taka insem tawn tur an ni a. Mahse, an rihna an inpekchhawn tawn hma a, an keh mai chuan kawngah khuar leh khi a lo insiam vat ṭhin. Kan lung thlan te, rihna do zo tawk ngei turin a lenzawng pawh kan ruahman a ngai tihna a ni. Entirna lo pe ta ila, RCC In sang sak a, a rih viau dawn chuan a ban kan tilian ṭhin a, a foundation pawh zau zawkin kan chhung ṭhin ang hi a ni.

Lung lian zawk remkhawm (stone to stone skeleton) ah thawrawng (void) tam deuh ṭhin mahse, rihna do let theihna an nei ṭha zawk. Hemi avang hian, lung keh tur hisap hian a tirah lung lian deuh hi hmang ta ila, rihna dolet a chak zawk bakah tui inpaihna (drainage system) a pui tha zawk bawk dawn a lo ni.

Lirthei rihna kawngpuia a lokalin a rihna in a thlen/ tuam chin (load influence area) a zirin kawng hi a tlo in a tlo lo thei a. Kawngah rihna influence area a zim chuan rihna a kalbing a, rihna insemrualna (load distribution) a awm tha lo tihna a ni; kawng a tlo thei lo. Rihna thlen chin ti zau tur chuan rihna lo dawngtu kan tilian ang a, a hlawm lian (block/ slab action) in rihna an lo insemdarh thei ang a, kawngin a tlo phah bawk ang.

Alkatra kawng hi flexible pavement tih a nih angin, rihna pek a nihin a kul/ fan (elastic/ flexible) thei tur a ni. Kan kawnga kan hman lungte an fan theihna (elastic limit) a hniam avangin kan kawngte pawh hi sakhat lehzual (semi-flexible/ semi-rigid) a siam a ngai ta tihna a ni ang.

- H Laldintluanga & Dr J Malsawma, MZU