CC PH?ONG PHP PHN TCH, NH GI K?T QU? QUAN TR?C ?A K? THU?T N?N ??NG ?P CAO TRN ?T Y?U - ?NG D?NG CHO TUY?N ??NG VNH AI PHA NAM THNH PH? N?NG - GI TH?U C57 The methods for analysis and evaluation the geotechnical monitoring data of embankment on soft soil- Apply to the south road of Danang city- Package C57 NCS. Nguy?n Lan 1, TS. ?ng Vi?t Dung2, TS. Hong Ph?ong Hoa1, KS. Nguy?n Vinh 3 1Tru?ng ?i h?c Bch Khoa- ?i h?c N?ng; 2Gim d?c S? GTCT thnh ph? N?ng; 3Trung tm KHCN & Tu V?n d?u tu - HBK N?ng TM T?T: N?n d?t y?u thu?ng du?c x? l b?ng nhi?u phuong php khc nhau. Trong d phuong php s? d?ng thi?t b? thot nu?c theo phuong th?ng d?ng (Prefabricated vertical Drains - PVD) k?t h?p v?i gia t?i tru?c du?c ?ng d?ng kh ph? bi?n hi?n nay t?i m?t s? d? n c?a Vi?t Nam. Tuy nhin vi?c dnh gi ?n d?nh n?n trong qu trnh gia t?i cung nhu dnh gi d? c? k?t n?n ph?c v? cng tc d? t?i thi cng cc giai do?n ti?p theo cn thi?u nhi?u t li?u t?ng h?p. Bi bo gi?i thi?u cc phuong php dnh gi ?n d?nh, c? k?t n?n trong x? l n?n d?t y?u d?a trn d? li?u quan tr?c. ?ng d?ng cc ph?n m?m chuyn d?ng cho phn tch d?a k? thu?t hi?n nay (Chuong trnh PTHH- Plaxis, Sai phn h?u h?n - SETTLE 3D) vo bi ton phn tch ngu?c d? dnh gi c? k?t n?n, cung nhu cc Modul chuong trnh do nhm nghin c?u pht tri?n nh?m m?c dch t? d?ng ha trong vi?c dnh gi k?t qu? quan tr?c d?a k? thu?t. Nghin c?u d du?c ?ng d?ng dnh gi k?t qu? quan tr?c d?a k? thu?t du?ng vnh dai pha nam Thnh ph? N?ng - Gi th?u C57. T? kha: Quan tr?c, d?a k? thu?t, dnh gi c? k?t, ?n d?nh, d?t y?u. ABSTRACT: Soft soil usually processed by many different methods. In which, plug PVD's method in conjunction with preloaded is quite popular at many current projects in Vietnam. However, the evaluation of the stability of the loading process as well as evaluating the consolidation to unloading and construction the next stage lacks general documents. This paper introduces the evaluation methods of stability and consolidation for embankment on soft soil with PVD. Application of current specialized software for geotechnical analysis (FEM-Plasix program[6.], Finite differential method - SETTLE 3D) for back analysis to evaluate the consolidation, as well as modules developed by the group for the purpose of automation in the evaluation results of geotechnical monitoring. Applications evaluate results of geotechnical monitoring the beltway south of Da Nang City - Package C57. Keywords: Monitoring, geotechnical, consolidation evaluation, stability, soft soil. 1. ?T V?N ? Khi thi cng xy d?ng n?n du?ng d?p cao trn d?t y?u, h? mng do su,... thu?ng c yu c?u cng tc quan tr?c d?a k? thu?t t? lc b?t d?u thi cng v c th? ko di trong m?t th?i gian d?u c?a khai thc. M?c dch c?a quan tr?c trong giai do?n thi cng nh?m ki?m tra l?i cc s? li?u, k?t qu? tnh ton d d? bo trong bu?c thi?t k? cung nhu theo di c?nh bo k?p th?i cc s? c? c th? x?y ra trong qua trnh thi cng v thu th?p cc s? li?u quan tr?c lu qu trnh khai thc ph?c v? dnh gi t?ng th? di?u ki?n lm vi?c c?a k?t c?u theo th?i gian. Bi vi?t ny, h? th?ng l?i m?t s? bi?n php quan tr?c, thi?t b? quan tr?c, cc phuong php dnh gi k?t qu? quan tr?c d?a k? thu?t d?i v?i cc do?n du?ng c n?n d?p cao trn d?t y?u ph?c v? cng tc ra quy?t d?nh d? t?i, v cc v?n d? khc trong qu trnh thi cng m?t sdo?n n?n du?ng d?p cao qua n?n d?t y?u tuy?n du?ng vnh dai pha nam thnh ph? N?ng (u?ng Nguy?n Tri Phuong di Ha Qu). 2. B? TR V L?P ?T H? TH?NG THI?T B? QUAN TR?C . Qu trnh nghin c?u thi?t k? k? thu?t, thi?t k? b?n v? thi cng, cc k? su d?a k? thu?t d xc d?nh cc m?t c?t ngang n?n du?ng c?n quan tr?c, n?i dung quan tr?c v yu c?u thi?t b? quan tr?c. Cc k? su quan tr?c can c? b?n v? b? tr h? th?ng quan tr?c d ph duy?t tri?n khai d? cuong chi ti?t cng tc quan tr?c d?a k? thu?t trnh k? su Tu v?n v Ch? d?u tu ph duy?t d? cuong. Cng tc l?p d?t thi?t b?, thu th?p, dnh gi s? li?u quan tr?c sau d du?c th?c hi?n theo d? cuong quan tr?c d du?c Tu v?n v Ch? d?u tu ph duy?t. B? tr di?n hnh c?a h? th?ng quan tr?c d?a k? thu?t n?n du?ng, xem trong Hnh 1 .Hnh 1: C?t ngang di?n dnh do?n c b? tr thi?t b? quan tr?c Cc thi?t b? quan tr?c du?c s? d?ng cho d? n bao g?m: + o ln b?ng bn ln v chuy?n v? ngang b? m?t: My th?y bnh v ton d?c di?n t?; + o m?c nu?c ng?m trong gi?ng quan tr?c m?c nu?c: Thu?c thp; + o chuy?n v? ngang theo chi?u su n?n: C?m bi?n Inclinometer, d?u d?c s? c?a hng Slope Indicator (USA)- gi th?u C13 v hng SISGEO- Italy (gi th?u C12 v C57); + o p l?c nu?c l? r?ng: Piezometer lo?i c?m bi?n dy rung, d?u d?c s? c?a hng Slope Indicator v SISGEO. M?t d? quan tr?c theo d? cuong l 1 l?n/ngy trong th?i gian d?p v thua hon trong th?i gian ch? c? k?t sau d. 3. PH?ONG PHP TH?C HI?N NH GI K?T QU? QUAN TR?C Thi cng xy d?ng n?n du?ng d?p cao trn d?t y?u v?i vi?c s? d?ng phuong php PVD k?t h?p v?i gia t?i tru?c yu c?u c?n ph?i dnh gi ?n d?nh trong qu trnh thi cng cung nhu dnh gi c? k?t th?c t? d? xc d?nh th?i di?m thi cng giai do?n ti?p theo: nh gi ?n d?nh: s? d?ng phuong php Matsuo- Kawamura [3.]. nh gi c? k?t: - Phuong php Asaoka [4.]; - Phuong php phn tch ngu?c; - Phuong php dnh gi d? c? k?t theo k?t qu? quan tr?c p l?c nu?c. 3.1. Ph?ong php Matsuo Kawamura: Co s? d? li?u ph?c v? dnh gi: s? li?u quan tr?c ln v quan tr?c chuy?n v? ngang (Inclinometer) Theo [3.], Phuong php ny d?a trn kinh nghi?m k? thu?t cho th nghi?m n?n d?t d?p ph h?y. K? thu?t ny l m?t phuong php so snh tuong quan di?u ki?n n?n d?t thi cng v tnh tr?ng ph ho?i trong qu trnh thi cng. Phuong php ny ch? ra nhu hnh du?i dy: Hnh 2 gi?i thi?u bi?u d? dng dnh gi ?n d?nh, du?ng quan h? c?a (h v h/s) du?c th? hi?n trn bi?u d? v: + Khi hu?ng mui tn mu tr?ng (I ? III): ?n d?nh; + Khi hu?ng mui tn mu den (I ? II): C xu hu?ng m?t ?n d?nh nhanh. Hnh 2: bi?u di?n bi?u d? cho dnh gi ?n d?nh, du?ng quan h? c?a (h v h/s) du?c th? hi?n theo Matsuo-Kawamura 3.2. Ph?ong php Asaoka: Co s? d? li?u ph?c v? dnh gi: d?a vo s? li?u quan tr?c ln. Theo[4.], Asaoka d ch?ng minh r?ng n?u chia du?ng cong quan tr?c ln thnh nhi?u di?m Si c cc kho?ng th?i gian b?ng nhau th khi v? tr?c d? th? v?i tr?c honh l Si v tr?c tung l Si+1 th cc di?m d l du?ng th?ng. i?u ny ch? dng khi t?i tr?ng tc d?ng l h?ns?, thu?ng ?ng v?i giai do?n d?p t?i l?n nh?t (?nh hu?ng m?c nu?c cung s? lm cho cc di?m l?ch nhau). ? ln cu?i cng l di?m giao nhau gi?a du?ng n?i cc di?m v du?ng k? t? g?c t?a d? m?t gc 45 d?. C th? so h?a nhu sau: Hnh 3: So h?a tnh ton d? ln cu?i cng b?ng phuong php Asaoka 3.3. Ph?ong php phn tch ng??c: Co s? d? li?u ph?c v? dnh gi: D?a vo s? li?u quan tr?c ln, quan tr?c m?c nu?c ng?m v tnh ch?t co l cc l?p d?t y?u, v?t li?u n?n d?p, bi?n php x? l d?t y?u. Phuong php ny th?c hi?n d?a trn vi?c tnh ton l thuy?t d? ln ?ng v?i cc th?i di?m tru?c khi l?p d?t PVD v sau khi l?p d?t, v?i cc chi?u cao d?p khc nhau, m?c nu?c t?ng th?i di?m khc nhau ?nh hu?ng d?n ?ng su?t h?u hi?u khc nhau. u?ng cong ln tnh ton t? t?t c? cc y?u t? ph?i d?t du?c trng kh?p tuong d?i v?i du?ng cong quan tr?c ln trn co s? hi?u ch?nh thng s? n?n d?t ph h?p v?i th?c t? t? cc k?t qu? th nghi?m tru?c d, d?c bi?t l cc thng s? v? ch? s? nn Cc v h? s? c? k?t ngang Ch. T? d s? xc d?nh du?c dln so c?p v th? c?p cu?i cng. 3.4. Ph?ong php dnh gi d? c? k?t theo k?t qu? quan tr?c p l?c n??c: Co s? d? li?u ph?c v? dnh gi: k?t qu? quan tr?c p l?c nu?c l? r?ng v m?c nu?c ng?m. p l?c nu?c l? r?ng th?ng du tang ln do qu trnh gia t?i v tiu tn d?n v? gi tr? "0" khi c? k?t d?t 100%. ? c? k?t theo p l?c nu?c: UWP% = (CSmax - EPWP)/ CSmax*100% trong d: CSmax (Max Consolidation stress): p l?c c? k?t l?n nh?t; EPWP (Excess pore water pressure): p l?c nu?c l? r?ng th?ng du; EPWP = PWP - SWP; PWP (Pore water pressure): p l?c nu?c l? r?ng; SWP (Static water pressure): p l?c nu?c tinh. 4. PH?N M?M ?NG D?NG PHN TCH NG??C Ty theo di?u ki?n s?n c c?a don v?, c th? s? d?ng m?t s? ph?n m?m phn tch d?a k? thu?t sau dy cho bi ton n?n du?ng d?p cao trn d?t y?u c s? d?ng PVD Plaxis [6.] c?a H Lan (Hnh 4), Settle 3D (Canada) [7.], ho?c m?t s? ph?n m?m t? vi?t c?a cc cng ty nhu One-Consolidation (hng TOA,Nh?t),...Chuong trnh Plasix d?a trn phuong php ph?n t? h?u h?n (PTHH) kh m?nh cho nhi?u bi ton d?a k? thu?t khc nhau. Tuy nhin, cc tham s? d?u vo cho cc m hnh d?t tuong d?i ph?c t?p c?n cc th nghi?m ph?c t?p hon. Chuong trnh Settle 3D d?a trn phuong php sai phn h?u h?n cho d? gi?i bi ton c? k?t cho n?n nhi?u l?p c giao di?n d? h?a kh m?nh, nh?p li?u thu?n l?i v c m?t nhi?u tnh nang chuyn d?ng cho bi ton n?n d?p cao trn d?t y?u c PVD thi cng nhi?u giai do?n nhu tnh nang phn tch ngu?c xc d?nh chi?u cao gia t?i tru?c d? d?t d? c? k?t yu c?u ? m?t th?i di?m nh?t d?nh. Hnh 4: M hnh PTHH bi ton N?n d?p trn d?t y?u c PVD thi cng nhi?u giai do?n. Settle 3D c r?t nhi?u d?ng k?t qu? phn tch du?c xu?t ra du?i d?ng bi?u d?, d?ng b?ng, xu?t d?ng d?nh d?ng Excel d? d? dng k?t n?i v?i cc ph?n m?m phn tch v dnh gi khc (Hnh 5 v Hnh 6). Hnh 5: Giao di?n chnh chuong trnh Settle3D. a) Giao di?n m t? n?n d?t y?u b) Giao di?n m t? n?n du?ng c) Bi?u d? ln theo th?i gian d) Bi?u d? p l?c nu?c l? r?ng th?ng du theo th?i gian. Hnh 6: Giao di?n nh?p li?u v bi?u d? k?t qu? ph?n m?m Settle3D. e) K?t qu? tnh chi?u cao gia t?i tru?c theo m?c tiu d? ln 5. T? ?NG HA TRONG PHN TCH V NH GI K?T QU? QUAN TR?C ?A K? THU?T: Cc chuong trnh phn tch Plaxis, Settle3D chua c tnh nang k?t n?i v?i cc d? li?u quan tr?c v k?t h?p v?i k?t qu? phn tch ngu?c d? th? di?n cc d? li?u phn tch l thuy?tquan tr?c hi?n tru?ng trn cng m?t d? th?. T? cc phuong php dnh gi ?n d?nh cung nhu dnh gi c? k?t d nu ? m?c 2, k?t h?p v?i ph?n m?m chuyn d?ng nu trn, nhm tc gi? d pht tri?n thm cc m dun chuong trnh vi?t trn ngn ng? C# ph?c v? cng tc t? d?ng ha trong qu trnh phn tch v dnh gi k?t qu? quan tr?c d?a k? thu?t. ?ng d?ng dnh gi k?t qu? quan tr?c d?a k? thu?t du?ng vnh dai pha nam thnh ph? N?ng - gi th?u C57. So d? kh?i t?ng qut cc m dun chuong trnh pht tri?n thm nhu Hnh 7. Hnh 7: So d? kh?i cc chuong trnh con ESTAB (dnh gi ?n d?nh); ESA (dnh gi d? ln cu?i cng theo Asaoka); BAKANA (Phn tch ngu?c). a) Giao di?n chuong trnh ESA b) Bi?u d? d? bo ln cu?i cng theo Asaoka c) Giao di?n,k?t qu? chuong trnh ESTA d) Nh?p d? li?u n?i suy e) Giao di?n chuong trnh BAKANA f) K?t qu? phn tch ngu?c theo d? ln-th?i gian Hnh 8: M?t s? giao di?n v bi?u d? k?t qu? c?a cc chuong trnh con S? d?ng cc chuong trnh con l?p du?c cng v?i chuong trnh Settle 3D, ?ng d?ng dnh gi d? t?i (chuy?n giai do?n) cho n?n du?ng d?p cao qua d?t y?u c b? tr h? th?ng quan tr?c - gi th?u C57- du?ng vnh dai pha nam thnh ph? N?ng c k?t qu? theo b?ng 1. B?ng 1: K?t qu? dnh gi c? k?t d? chuy?n giai do?n thi cng gi th?u C57 ? ln cu?i cng ? ln ? 12/08/2013 ? ln ? th?i di?m ti?p t?c M?t c?t SPF1 (cm) Phn Sp (cm) U(%) Phn giai do?n khc Ngy ti?p t?c Asaoka tch ngu?c Quan Asaoka tr?c tch ngu?c SpA (cm) G khc Km0+280 117.9 118.5 106.7 90.50 90.04 106.65 Ngay by gi? Km0+460 171.5 173 133.4 77.56 77.11 155.70 2/11/13 6. 4. K?T LU?N V KI?N NGH?: Qua cng tc tham gia l?p d? cuong, l?p d?t v?n hnh thi?t b? quan tr?c, thu th?p v phn tch bo co k?t qu? quan tr?c ph?c v? ch?n don v quy?t d?nh d? t?i, chuy?n giai do?n thi cng cc gi th?u C13, C12 (d thi cng m?t du?ng) C57 (dang thi cng) tuy?n du?ng vnh dai pha Nam thnh ph? N?ng, c m?t s? nh?n xt nhu sau: 1. Cng tc quan tr?c d?a k? thu?t cho cc do?n n?n d?p cao qua d?t y?u l c?n thi?t, n cho php thu th?p cc d? li?u khch quan bi?u th? ?ng x? c?a n?n d?p theo cc giai do?n thi cng khc nhau d? so snh d?i chi?u v?i k?t qu? phn tch l thuy?t m s? li?u d?u vo c?a phn tch mang nhi?u y?u t? khng ch?c ch?n. Phn tch d? li?u quan tr?c theo cc phuong php th?c nghi?m-k?t h?p phn tch nu trn cho php ra quy?t d?nh ph h?p v c co s? tin c?y hon v? th?i di?m d? t?i, chuy?n giai do?n thi cng; xc d?nh chi?u cao gia t?i thm v th?i gian ch? c? k?t trong tru?ng h?p mu?n rt ng?n th?i gian thi cng d?p n?n ho?c di?u ch?nh ti?n d? d? n (d p d?ng cho gi th?u C12). 2. H?u h?t qu trnh phn tch ngu?c d? kh?p d? li?u ln-th?i gian v p l?c l? r?ng th?ng du-th?i gian d?u c?n ph?i di?u ch?nh cc tham s? m hnh n?n ban d?u, s? vng l?p di?u ch?nh ty theo kinh nghi?m ngu?i phn tch, kh? nang ph?n m?m s? d?ng, d? chnh xc cc s? li?u kh?o st n?n ban d?u. Phuong php phn tch ngu?c l du?ng l?i ph h?p v hay du?c p d?ng khng nh?ng trong d?a k? thu?t m cn trong nhi?u bi ton ch?n don k?t c?u khc. N cng c uu th? v kh? thi trong di?u ki?n cng ngh? c?m bi?n v do d?c ngy cng pht tri?n. 3. K?t qu? phn tch ngu?c, d? bo th?i di?m d? t?i, tnh ton tang thm chi?u cao gia t?i d? rt ng?n th?i gian ch? c? k?t, dnh gi ?n d?nh d p d?ng cho d? n d ph h?p v?i ?ng x? c?a n?n v k?t qu? quan tr?c. 4. Nh? c cc ph?n m?m phn tch c th? d? dng tnh ton d? ln c? k?t c?a m hnh k? c? d? ln so c?p v d? ln th? c?p, cho nn c?n xc d?nh r yu c?u v? d? ln c? k?t d?t du?d? chuy?n giai do?n thi cng o du?ng theo tiu chu?n 22TCN 244-98 90% bao g?m c? d? ln so c?p v th? c?p d? gi?m d? ln cn l?i khi thi cng o du?ng, gi?m nguy co hu h?ng k?t c?u o du?ng do d? ln cn l?i qu nhi?u gy ra. 5. Cc chuong trnh con d l?p du?c s? d?ng kh hi?u qu? d? x? l cc d? li?u quan tr?c, k?t n?i v?i ph?n m?m phn tch chuyn d?ng trong cng tc phn tch ngu?c. Cc chuong trnh con c th? pht tri?n thm nhi?u tnh nang m?i nhu: T? d?ng nh?n s? li?u t? b? thu d? li?u (dataloger) c?a thi?t b?; k?t n?i m?ng lu?i c?m bi?n khi quan tr?c lu di; giao ti?p m?ng internet; dnh gi t? d?ng v hi?n th? k?t qu? theo th?i gian th?c trn n?n Web. 6. M?t s? bi h?c kinh nghi?m rt ra du?c l: + C?n phn tch m hnh k? cng d? xc d?nh v? tr b? tr c?m bi?n quan tr?c t?i cc noi c ?ng x? (ln, chuy?n v?) b?t l?i nh?t ph h?p v?i c?u t?o n?n s? thi cng. + Trong qu trnh khoan, l?p d?t c?m bi?n piezometer quan tr?c p l?c l? r?ng trong cc l?p d?t dnh (st) c?n quan st, dnh gi m?u d?t khoan ln t?i hi?n tru?ng, d? trnh d?t piezometer vo v? tr th?u knh l?p ct (c?c b? ho?c do kh?o st bu?c tru?c d chua chnh xc) d? thu th?p s? li?u v xc d?nh p l?c l? r?ng th?ng du ph h?p hon. + Trong tru?ng h?p cc do?n n?n d?p cao trong m?t d? n c b? tr nhi?u v? tr quan tr?c g?n nhau, nn phn tch thm cc phuong n b? tr thi?t b? h?p l hon cho c? d? n d? ti?t ki?m kinh ph quan tr?c. C th? dng nt c?u hnh-tr?m t?ng (node-base), trong d cc nt k?t n?i v?i cc c?m bi?n ? m?t tr?m quan tr?c (m?t c?t) v truy?n d? li?u v? tr?m t?ng b?ng du?ng truy?n c dy ho?c khng dy. Cng ngh? quan tr?c p d?ng cho d? n ny dng b? d?c d? li?u c?m tay, thu th?p v phn tch bn t? d?ng. Qua kinh nghi?m thu du?c c th? m? r?ng p d?ng cho cc h? th?ng quan tr?c d?a k? thu?t t? d?ng qui m l?n, quan tr?c lu di, hi?n th? s? li?u v k?t qu? dnh gi theo th?i gian th?c trn n?n web l hon ton kh? thi. TI LI?U THAM KH?O [1.]B? Giao thng v?n t?i. Qui trnh thi?t k? x? l d?t y?u trong xy d?ng n?n du?ng 22TCN 244-98 [2.]Trung tm KHCN & Tu v?n d?u tu-Tru?ng HBK N?ng, Cc bo co k?t qu? quan tr?c d?a k? thu?t d? n du?ng Nguy?n Tri Phuong di Ha Qu, TP. N?ng, 2012-2013. [3.]Minoru Matsuo-Kunio Kawamura, Diagram for construction control of embankment on soft ground, Soil & Foundation Vol.17, No.3, Sept.1977 [4.]Akira Asaoka, Observation procedure of settlement prediction, Soil & Foundation Vol.18, No.4, Sept.1978 [5.]Rocscience In (2007-2009), Settle3D- Settlement and Consolidation analysic, Theory manual. [6.]http://www.plaxis.nl/plaxis2d/manuals/ [7.]http://www.rocscience.com/products/7/Settle3D