While they can happen anywhere, the states most prone to sinkholes are Florida, Alabama, Texas, Missouri, Pennsylvania, Tennessee, and Kentucky. Sinkholes are created when the terra firma below the exterior of the ground has been slowly dissolving and forming cavernous spaces that eventually lose the ability to hold up the surface.The types of rock that are under the surface that can be most easily eroded by water are salt beds, limestone, and other carbonate rock such as dolomite. Sinkholes can range from 3 feet to a couple of thousand feet in depth and diameter. No matter what size, they can cause serious and significant damage to roads, homes, and property.
Types of Sinkholes
It is important to note that there are different types of sinkholes, the most common of which are dissolution, cover-collapse, and cover-subsidence. These range in severity, depth and danger level, with variable costs associated with damages.
Dissolution of carbonate rocks is the most extensive at the point where water first contacts the underground rocks’ surface. Aggressive dissolution can also occur where water is concentrated in vulnerabilities of the rock structure along fractures, joints, bed planes, and in the water-table fluctuation area.
Surface and rainfall water percolates through joints in the rock, and fragments of the rock separate from the face of the surface, eventually forming a small depression. Surface drainage from an exposed depression can become focused, speeding up the dissolution process. Debris can potentially be carried into a developing sinkhole and may block the outflow, which can pond the water and lead to the creation of wetlands, such as in Florida.
Cover-subsidence usually develops slowly over time where the sediments are most vulnerable and sand infiltrates them. Granular sediments splinter and break into peripheral spaces within the lower rock beds, making room for overlying sediments to settle into the open areas. After more dissolution and infilling, a noticeable depression is formed in the land on the surface.
This will slowly continue to form into a depression that ranges from a few inches to more than a few feet. Cover-subsidence tends to be smaller and more undetectable for a longer amount of time when the sediments have clay or the cover material is thicker.
Cover-collapse develops when sediments break down into a cavity, leading the cohesive covering sediments to form an arch. The cavity moves upward through progressive roof collapse and eventually reaches the ground surface, forming sudden sinkholes. They form because there is a significant presence of clay in the covering sediment. These sinkholes can be very dangerous and destructive, for it can seemingly happen in an instant, causing extensive and possibly very costly damage.
Human Activity Can Also Cause Sinkholes
Sinkholes can also be created through human activity such as drilling vibrations, heavy traffic, and through changes in land such as creating a run-off pond or groundwater pumping. Wherever there may be a high incidence of human activity, the land should be analyzed for dangerous side effects like sinkholes.
It’s easy to put the natural phenomenon of sinkholes into a few paragraphs of writing, but nature is dangerous and unpredictable, and we learn something new every day. A sinkhole’s impact will likely result in very costly damage. It’s so important for yours and others’ safety to consult a geotechnical engineer to analyze your soil and foundation before planning any construction, in order to prevent damage or injury from a sinkhole. Doing so will give you peace of mind that the structural integrity of your ground will permit a safe, stable construction project now and well into the future.
Ingawa zinaweza kutokea mahali popote, majimbo yanayoathiriwa zaidi na mashimo ni Florida, Alabama, Texas, Missouri, Pennsylvania, Tennessee, na Kentucky. Sinkholes hutokea wakati terra firma chini ya nje ya ardhi imekuwa polepole kufutwa na kuunda cavernous nafasi kwamba hatimaye kupoteza uwezo wa kushikilia juu ya uso. aina ya miamba ambayo ni chini ya uso ambayo inaweza kuwa rahisi zaidi eroded na maji ni chumvi, chokaa, na miamba nyingine carbonate kama dolomite. Sinkholes inaweza kuanzia mita 3 hadi mita elfu mbili kwa kina na kipenyo. Haidhuru ni kubwa kadiri gani, zinaweza kusababisha uharibifu mkubwa na mkubwa kwa barabara, nyumba, na mali. Aina ya sinkholes: Kuna aina tofauti za sinkholes, ambayo ni ya kawaida zaidi, ambayo ni kufutwa, kufunikwa-kuanguka, na kufunikwa-subsidence. Hizi mbalimbali katika ukali, kina na kiwango cha hatari, na gharama tofauti kuhusishwa na uharibifu. Ufumbuzi wa miamba ya kaboni ni mkubwa zaidi katika hatua ambapo maji kwanza huwasiliana na uso wa miamba ya chini ya ardhi. Uharibifu wa maji unaweza kutokea pia ambapo maji huchanganyika katika sehemu dhaifu za muundo wa mwamba kando ya maporomoko, viungo, ndege za kitanda, na katika eneo la kutofautiana kwa maji ya chini ya ardhi. Maji ya juu na ya mvua huingia kwenye miundo ya mwamba, na vipande vya mwamba hutenganishwa na uso wa mwamba, na hatimaye hufanyiza mteremko mdogo. Mtiririko wa maji kutoka kwenye shimo linalofunuliwa waweza kukazia fikira, na kuharakisha mchakato wa kuyeyushwa. Mvua inaweza kuingizwa ndani ya shimo linaloendelea na inaweza kuzuia mtiririko wa maji, ambayo inaweza kuhifadhi maji na kusababisha uundaji wa maeneo ya mvua, kama vile Florida. Cover-subsidence kawaida inaendelea polepole kwa muda ambapo sediments ni zaidi ya kuathirika na mchanga infiltrates yao. Matope yenye chembechembe hutenganishwa na kuvunjika katika maeneo ya pembeni ndani ya matope ya chini, na kufungua nafasi kwa matope yaliyo juu ya matope ili kuhamia maeneo ya wazi. Baada ya kuyeyuka zaidi na kujazwa, mteremko unaoonekana hufanyizwa katika ardhi juu ya uso. Hii itazidi kuunda polepole katika msukosuko ambao unatofautiana kutoka inchi chache hadi zaidi ya futi chache. Cover-subsidence huwa ndogo na zaidi undetectable kwa muda mrefu wakati sediments kuwa udongo au nyenzo ya kifuniko ni nene. Cover-kuanguka inaendelea wakati sediments kuvunja chini katika cavity, kuongoza cohesive kufunika sediments kuunda arch. Shimo hilo husonga juu kupitia kuporomoka kwa paa kwa kasi na hatimaye hufikia uso wa ardhi, na kufanyiza mashimo ya ghafula. Wao hufanyizwa kwa sababu kuna udongo mwingi katika matope yanayofunika. "Hizi ""sinkholes"" zinaweza kuwa hatari sana na za uharibifu, kwa sababu inaweza kutokea kwa kuonekana katika muda mfupi, na kusababisha uharibifu mkubwa na uwezekano wa gharama kubwa." Sinkholes inaweza pia kuundwa kupitia shughuli za binadamu kama vile vibrasia vya kuchimba visima, trafiki nzito, na kupitia mabadiliko katika ardhi kama vile kuunda dimbwi la kukimbia au pampu ya maji ya chini ya ardhi. Mahali popote ambapo kuna uwezekano wa kuwa na shughuli nyingi za kibinadamu, ardhi inapaswa kuchambuliwa kwa athari hatari kama vile sinkholes. Ni rahisi kuweka jambo la asili la sinkholes katika mafungu machache ya kuandika, lakini asili ni hatari na unpredictable, na sisi kujifunza kitu kipya kila siku. Uharibifu wa shimo la chini ya ardhi huenda ukasababisha uharibifu wa gharama kubwa sana. Ni muhimu sana kwa usalama wako na wa wengine kushauriana na mhandisi wa geotechnical kuchambua udongo wako na msingi kabla ya kupanga ujenzi wowote, ili kuzuia uharibifu au jeraha kutoka kwa shimo. Kufanya hivyo kutakupa amani ya akili kwamba uadilifu wa muundo wa ardhi yako utaruhusu mradi wa ujenzi salama, thabiti sasa na kwa muda mrefu katika siku zijazo.