I Khoa htx • Cong nghe va Doi mdi sang tao
CHONG XOI BE MAT VA GIAM TRlTOT B0 DOC N I N DlTdNG THEO HO0NG THAN THIEN MOI T R O O N G
Nguyen O^c Manh, Nguyln e.nh Dung
^ ^ raring 0.1 hoc Ci.o thong van ta.
Viec Ung dung cac g i i i phap cong nghe mdi trong phong chong xoi mon be mat va trUcrt nong tai cac bd doc nen dUdng dao khong cht nham nang cao chat lUdng cac cong trmh xay dung ma con hUdng tdi gi^m thieu be tong hoa, thay the bang cac giai phap c6 the b^o ton thien nhien, phu xanh bdi tham thuc vat, dam bao canh quan moi trUdng de phat trjen ben vang. Gan day, giai phap cong nghe mdi bao ve bd doc^bang tham chong xdi mon dat MACMAT HS va Non-franie ket hdp phu xanh bang tham thiic vat hdp ly dang dUdc trien khai tai nhieu quoc gia tren the gidi, dUdc xem la giai phap hieu qu^
thay the be tong trong bao ve chong xdi mdn dat va trUdt ndng cac bd doc nen dUdng dao.
Xoi mbn ail va tniVt nong tr6n cac Del A6C n^n fliTdng
Qua trinh xdi mdn Id boat ddng dia ehat be mat, dUdi tac dung ehu yeu cua nudc (nudc mda, nudc mat), hay gid lam rua Irdi vd Idi eudn ede hal/manh vun dat da tren bd doc, hinh thanh cde ranh, khe hay cac mUdng xdi Qua trinh nay thudng bat dau Id nhdng vi tri dat da kem ben hon, mde dd phong hda manh hon. khdng ed Idp phu hay lop gia cd be mat Trong nhieu trudng hop, khi xoi mdn be mat phat tnen toi mdt mdc dd nao do cd Ihe lam phat smh trdd't nong tai eae bo dde ndy. NOI each khae. hien tdong
trddt ndng ngoai nguyen nhan do cdc tae ddng gay mat can bang dng suat khi ddo dal va thieu giai phap gia eo, dan den nude tham vdo khdi dat dd tren bd dde khi khdng dUde ehe phd be mat, thi xdi mdn dat cung la Ide nhan quan Irong.
Trong xay dung giao thdng ma ehu yeu la dudng bd va dddng sat, cd 2 loai nen dudng pho bien la dap va ddo. Nen dddng dap thuong d vung ddng bang hay eae khu vuc dia hinh thap. ngdde iai nen ddong dao thudng phd bien khi tuyen duong cat qua cac VI In doi nui eo dia hinh eao va dde.
Trong qua trinh thi edng bd doc, viee dao dat quy md ldn se lam thay doi eau true nen dat, dan tdi mat can bang dng suat, ldm phal sinh trdpl dat tai eac bd dde mdi dao [1-4], Khi trUdl dat tren cac bd doc, tuy theo dp sau mat trdpt hay gidi han mat on djnh ciia dat dd ma dddc ehia ra thanh ode dang Iruoi gom: trddt nong (Shallov^ Landslide) (dp sau
<5 m) vd trddt sau (Deep-Seated Landslide) (dp sau >5 m) [1-3].
Cung tai cac bd doe nen dudng ddo nhd vay, Idp phu thuc vat von cd b! boc bd. lam 'r, .^ ^ ri va phdi nhiem be mat dar v- -,,3^ cac dieu kien moi tru^- K.Ar,
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Khoa hgc - Cong nghe va Doi mdi sang tao I
Hinh 1. Trong co thii conj; cliong xdi mon khong hi?u qua Irt-n bo' doc du(Jng dao (dUcfng cao toe No! Bai • Lao Cai, 2015).
Dac biel, trong dieu kien khi hau nhiel ddi am nhu Viet Nam thudng ton tai dieu kien dja chat bat ldi, Ihanh phan dat da bien ddi phdc tap, vdi Idp vo phong hda day vd rat da dang, cung vdi lupng mda trung binh nam ldn (1.500-2.000 mm, tham ehi tren 4.000 mm), se la dieu kien rat thuan ldi ldm phal sinh hien tddng dat dd tren be mat bd dde nen dddng mdi ddo bj xdi mdn neu khdng cd idp ehe phii,
Vdi cdc bd dde nen dSp tnay cac bd doc Id nhien ed Idp dat mau gidu dinh dudng va du ddy, gi^i phap trdng eo Ihii cong dddc lua chon phd bien d nude ta hien nay. Vdi dieu kien dd, giai phap chdng xdi be mat nay khdng chi gi^i quyel lot ca ve yeu td ky thual - bao ve bd dde, ma cdn tao tham my va sinh thai neu duy tri Idt Idp CO phu xanh. Tuy nhien, lai cac nen dudng dao va Id ede Idp da phong hda, giai phap trdng CO truyen Ihong Ihudng gap kho khan, tham chi that bai (hinh 1)
Hinh 2. Che phu be m.il IHI dm b.ing da xay va be tong phun khong hiOu qua khi ap dung khong phii hop IdacJng cao toe Npi B.ii - Lao Cai, 2017).
Tai hau het bd dde nen dddng dao, eae giai phap che phu be mat bd dde Ida chon phd bien nhdng nam qua tai Viet Nam la: sD dung Idp da hoc xay kin, lap ghep cae tam be tdng edi thep phu kin, ket hdp ede khung dam be ldng cdt thep vdi tam be tdng cd lo de Irdng co Ihii cdng, hay che phu bdng Idp be long phun true tiep cd hode khdng cd lUdi thep... Tuy nhien. neu lua chpn khdng phu hpp vdi dac diem dia ehat va dja hinh. cdc giai phap ehe phu nay phan nao da iam tang them tai trong len bd doc, khi ma giai phap thoat nudc ngam khdng tdt lai de gdy tac dung ngUdc - bat ldi doi vdi sut trugt (hinh 2). Le dT nhien, viec sif dung be tdng hay dd xay
phu be mat bd dde se khd dcim bao ve my quan va sinh thai Ltfa chgn ch6ng xoi flat bd mdt va giam thi6u triM nOng bd d5c bdng cac giai phap linh hoat
De giai quyet cae khd khan neu tren, nhieu cdng nghe mdi da ddde nghien cdu. dp dyng, trong dd cd 2 cdng nghe ddde nhieu qude gia tin dung Id Non-frame (ket hpp ludi thep trdng ed bSng phun hat) vd tham MACMAT HS (phu be mat bd doc).
Giii phap Non-frame ket hpp ludi thep va phu xanh bang thUc vat
Non-frame la giai phap cdng nghe dupc Cdng ly vat lieu xdy dung Nippon Steel va Sumikin Metal Products phdt tnen Id nam 1996, hien dang dUde dp dung hieu qua tai Nhat Ban eung nhu mgt so ndde [5-8]. Ket cau ehinh ciia he thdng Non-frame gdm dinh dat hoac dinh da (soil nail/
rock bolt) neo gid va gia cd sau vdo khdi dat da. ban thep cd bu long xiet giO dau (dinh dat, dinh da) de lien ke't he thong eac day cap cudng dp cao khong gi Iren mat dat (hinh 3).
Hinh 3. So' d6 giai phap cong nghe Non-frame I
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I Khoa hgc - Cong nghe va Doi mdi sang tao
Trong qua trinh lam viec. luc doe theo dinh dat phat sinh khi khdi dat co c h u y i n vi, nhd ban m§t thep dau dmh va m a sat dpc true bSu vOa. dmh dat tao v u n g chiu nen va tang kha nSng chiu keo. khi do luc cat trong dinh dal sinh ra tai vi tri mat truol se chdng lai ehuyen vi cua Idp dat trddl, giam nguy cd IrUdl dat, dac bipt h i ^ u qua ngSn chSn truol n d n g Mang cap noi ddde lien kdt va ghim gid Igi eae dau dmh dat Iren mat bd dde nhd tam thep va bu ldng tao thanh mdt khdi Ihdng n h ^ l (h0 m g n g ludi cap vd dinh dat), chdng lai djch chuyen khoi dat Irupl ndng - dn dmh khdi dat tren bd dde. Nghia la, luc gia cddng t d dinh dat (bao gom ca ldi va vQa) se chdng lai sp dich c h u y d n trugt cua khdi dat doe theo dinh C u n g vdi do mdt phan lue chdng e^t se ddpc phat huy bdi ldi eua dinh dat (thanh thep).
t d phan m u i dinh (vung dat dn d m h ben trong) tdi lop dat co dich ehuyen Irdol c a n gia c d . Khi Idp dcit cd chuydn vi trUdI xudng thi ldc c^t eua dinh dat. lue ma s d i doc true dinh dat va ldc lien kel he thdng day cdp tren be mat bd dde se ldn dan tdi khi ldn hdn ide gay truol, b d dde se ddOc dn dinh [9],
Giai phap Non-frame dSc biet hieu q u ^ ehdng trupt dat ndng vdi v u n g dcil trddt sau 2-3 m, rat Imh hoat theo dia hinh ma khdng can dao dat hay chat pha tham thuc vat hien eo H o n the, giai phap nay cdn c d the su d u n g kel hpp
Mil Ml.) till cCmti wmi;
Hinh 4. Cia cobodoc bing giai phap bd sung Idp ludi thep xoan phii tren mat bd doc eung lien ket vdi he cap. sau dd phun hat ed tao Idp phu thuc vdt mdi, se rat hi?u qua khong ehi phdng chong irudt ndng m a cdn ehdng xdi mon dal va phii xanh smh thai rai hieu qua (hinh 4)
Tham chdng xoi mon dat MACIV1AT HS
Tham chong xdi mdn dal M A C M A T HS (MACMAT High Strength) cua Hdng Maccafern (Italia) ddde cau thanh bdi su ket hop cd ludi thep cudng dd eao ehdng an mon xoan kep vdi he IdOi dia ky thuat dang 2D hoae 3D HDPE (high density polyethylene) ed bd sung m u n ChUa hoae khong ehUa hat cd hay hat thue vat (hinh 5).
S.iiJ-1 rh,ini;ilii.onf;
tongnghe Non-frame tai Nhat Ban 191.
Chung dudc san xuat tai n h a mdy, kich thude cupn tieu c h u a n rpng 2 m va ddi 30 m. Loai t h a m nay CO eUdng do chiu keo ldn ( 3 5 - 1 7 0 kN/m), ddde thi c d n g d d n g i ^ n , phu hdp bd dde nen d a o eao va dp doe ldn (>45''), c h o p h e p t h o a t ndde trong dat I d d o , d§ d a n g g i d va khdi phuc Idp dat m a u de tao tham thdc vat x a n h tot, D a c b i e t khi sd d u n g ket h p p vdi d i n h dat, khdng chi giup c h d n g xdi m d n dat va tao tham thde vat tdt, giai phap cdng nghe nay edn c h o p h e p gia ed c h d n g trddt n d n g eho cae b d dde nen d a o [10]. N g u y e n ly dn djnh khdi dat tren b d dde ed n g u y c d trddt khi s d d y n g d i n h d a l vdi I h a m tvlACMAT H S t d d n g I d n h d giai phap N o n - f r a m e n h d d a m d la d I r e n .
^mm
Hinh 5. Tham chong xoi tnon dat tren bb doc MACMAT HS
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Khoa hgc - Cong nghe va Doi mdi sang tao I
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Hinh 6. Bao ve hb doc b^ng giai phap c Nhd hieu qua ehdng xoi mdn dal be mat bd dde tot va phu xanh sinh thdi dep cua giai phap cdng nghe nay, nen khong chi eac nudc ehau Au, chau My, Trung Qudc... ma ngay tai Indonesia, Philippines hay Malaysia ede nude cd nhieu tddng ddng vdi dieu kien ty nhien nhU ndde la cung sif dyng Ihiim MACMAT HS ngay cang nhieu.
Viet Nam la qude gia cd dieu kien dia hinh vung nui dde sdt ven bien, ed dien tfch vung nui chiem Iren 50% tdng dien tich va hdng nam deu phai hung chiu nhieu edn bao, vdi lddng mda ldn. Tai Viet Nam, cac tuyen dddng giao thdng tai vung nui phia Bae, tuyen dudng qudc Ip vung mien Trung, Nam Trung Bd deu bi de dga bdi hien lupng xdi mdn be mat, dac biel la eae loai trUpt ndng cd mat IrUdt Id 0,5 den 3 m xay ra rat phd bien. Hien tUdng sat trddt dd't lai thudng xuat hien tai nhOng khu vuc CO eac edng trinh xay dung, khu dong dan ed va ca nhOng
Sau S I h j n g [hi ciin^
ong nghe tham chong x ndat |iO|.
khu vuc cd nhOng di tieh Ijch si/, di san vdn hoa. Vi vay, viec tim ra va ap dung phddng phap gid dn dinh mdi dde nhung van giQ ddde eanh quan mdi trudng de thay the eho cae phddng phdp hien nay la thde sd can thie't. Dd nhan thay, eac giai phap edng nghe ehdng xdi mdn dat vd bao ve bd dde nen dudng ddo vung nui bdng Non- frame hay tham MACMAT HS khong chi dap dng lot ve lieu ehi ky thuat, ma cdn tai tao tham thuc vat de xanh hda cac bd dde, bao ve mdi trudng Id nhien.
Vdi dieu kien ty nhien Iddng ddi gidng nhau, viee tham khao cae ket qua nghien edu hay ap dung thd nghiem cae edng nghe mdi phong ehdng sat trddt dat cua cae qudc gia phdt then vao Viet Nam thuc sU cd y nghTa va can dude tien hanh eang sdm edng tdt -^
TAI LIEU THAM KHAO
[1] Nguyen Difc Manh (2017).
"Nghien cuu giai phap to tigp xU ly sut trUdt bo doc quy mo Ion khu vUc doi Ong Tuong, Ihanh pho Hda Binh".
Tap chf Giao thong van tai dien ft>. so 11/2017, http,//www-tapchigiaottiong.
vn/nghien-cuu-giai-phap-lo-hop-xu-Iy- sut-lruot-bo-doc-quy-mo-lon-khu-vuc- doi-ong-tuong-tp-hoa-binh-d52524 titml.
[2] Nguyen DUc Manh (2018),
"Nghien cUu Ung dyng giai phap dat dap col Geocell k^t hop dmh dat va tudng coc khoan nhoi xU ly sU co SMt trUOt du6ng Hoang Dieu tai Itij Iran Sa Pa", Tap chi Khoa hoc giao thong v$n tai. 11, tr 233-241.
[3] Nguyen Difc Manh. Le Thj Hong Van, Nguyen Thai Linh (2020), "Nghien cUu anh hudng cCia dUdng mUC nUdc va giSi phap xLf ly syt truot bd d6c khu tSi dmh cU Nam Khao, huyen Mudng Te.
tinh Lai Chau". Tap chi Dia l<y thu$t. so 1/2020, tr.28-35
[4]NghiemM Quang,H.Nakamura.
K. Siraki (2003), "Analysis of rool reinforcemGnt at slip surlace", Journal ol The Japan Landslide Society, 40(4), pp.44-52,
[5] Nghiem M. Quang, H, Nakamura, K. Siraki (2004), "Slope slability of forested slopes considering effect ol tree root and steel bar reinforcement". Journal of The Japan Landslide Society. 41(3), pp.264-272,
[6] Nguyen Sy Ngpc (2006), Cac yeu to anh hudng tdi do dn dinh bd doc 6 Viet Nam, Tuyen tap cdng Irinh Hpi nghj khoa hoc Cd hoc da - Moi trudng rdi loan quoc lan thU 5, Hoi Co hgc da Viet Nam
[7] https //www ns-kenzai.co.jp/
english/043non_frame,hlm!.
[8] http.//o-taka.co | p / e n / n o n - frame/.
[9] https7/www bosat-|p org/en/
solution/pdf/25,
[10] https;//www,maccaferri,com/
solutions/slope-protection/
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