SOIL

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AS 1012.3.3-1998

AS 1012.3.3-1998

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Tiu chun th nghimTIU CHUN AUSTRALIA

AS 1012.3.3-1998TIU CHUN TH NGHIM B TNG

Phng php 3.3.: Xc nh cng ca b tng bng dng c Vebe Th nghim Vebe.

LI NI UTiu chun ny do u ban tiu chun Australia BD/42 son tho, Cc phng php th nghim b tng thay th tiu chun AS 1012.3 -1983. Tiu chun ny l mt trong nhiu tiu chun p dng cho vic ly mu v th nghim b tng.PHNG PHP1 PHM VI P DNGTiu chun ny a ra phng php xc nh tr s Vebe ca b tng c c ht danh ngha ca ct liu khng vt qu 40 mm.

Ch thch Tiu chun ny c th bao gm thit b, cch thc hin v cc vt liu nguy him, nhng tiu chun ny khng cp n tt c nhng vn an ton lin quan n vic s dng n. Trch nhim ca ngi s dng tiu chun ny phi thit lp ni quy an ton ph hp v nhng hng dn thc hnh v y t cng nh phi xc nh nhng hn ch cn iu chnh cho ph hp trc khi s dng.2 TI LIU VIN DNCc ti liu sau y cn tham kho:AS 1012 Cc phng php th nghim b tng

1012.1 Phng php 1: Cch ly mu b tng ti

1012.2 Phng php 2: Chun b hn hp b tng trong phng th nghim3 NGUYN TC

Phng php ny m t qui trnh xc nh thi gian cn thit mu b tng ti t m cht hon ton di mt tc ng rung chun. Ngi ta cho rng thi gian cn thit b tng t m cht hon ton di mt tc ng rung qui chun s khng thay i gia cc m trn b tng ring bit, nu cc t l cp phi trn v tnh cht ca cc vt liu trn gia cc m trn khng thay i.4 DNG C V THIT B 4.1 My o st My o st c trnh by bng s hnh 1 v bng hnh nh hnh 2. My ny bao gm cc b phn sau:

a) Thng cha Thng cha lm kim loi, hnh tr (A) c ng knh trong 240 5 mm v chiu cao 200 5 mm, kn nc, cng khng b bin dng khi s dng, c gn quai cm, khng b n mn. Thng cha phi c ngm y c th kp cht ln trn mt bn rung bng cc c tai hng. b) Khun Khun (B) c dng hnh nn ct vi kch thc bn trong nh sau:

I) ng knh y

200 5 mm

Ii) ng knh nh

100 5 mm

Iii) Chiu cao ng

300 5 mm

Khun c ch to bng kim loi c dy khng nh hn 1.5 mm, nh v y h v vung gc vi trc ca nn ct. Khun c b mt bn trong nhn v c quai d nhc ra khi b tng theo phng thng ng theo yu cu ca th nghim ny.

c) a Mt a (C) nm ngang, trong sut c gn cht vi thanh nh hng (J), c th trt theo chiu thng ng trong ng dn (E) bc bn ngoi, ng dn c gn vi mt tay (N) v c th c nh v tr nh inh vt (O). Tay N cn phu (D), y ca phu c t trn khun hnh nn ct khi khun c nh v ng tm vi thng cha. Tay (N) trt hoc gi c nh bng vt hm (F) trong ng M bt c nh vi bn rung (K). Khi t v tr ph hp th trc ca thanh nh hng v ca phu u trng vi trc ca thng cha. a trong sut c ng knh 230 1 mm v c dy 10 1 mm . Mt qu cn (P) c ng knh ti a 80 mm c t trc tip ln a sao cho khi lng ca c tp hp gm thanh trt, a v qu cn (P) bng 2750 50 gam.

d) Bn rung Bn rung (G) di 380 mm, rng 260 mm c trn bn ng gim xc bng cao su. My rung (L) c t trn (K). (K) t trn ba chn cao su v c c nh chc chn pha di. My rung hot ng vi tn s 50 1 Hz vi bin dao ng 0.5 0.02 mm.4.2 Thanh m: Thanh m dng m b tng trong khun, l mt thanh kim loi c ng knh 16 1 mm, di khong 600 mm v c t nht mt u c vut trn thnh hnh bn cu khong cch khong 25 mm vi bn knh khong 5 mm.Ch thch Thanh m c th c ni di vi mt tay cm bng ng nha, min l tng chiu di khng c vt qu 1000 mm.

4.3 ng h bm giy - ng h bm giy (hoc ng h eo tay) c th c c t nht n 0.5 giy.

4.4 Mui xc - Mt mui xc lm bng vt liu khng ht nc, khng b va xi mng n mn v ph hp xc c b tng ti.

Ch thch Mui phi ln xc c lng ct liu ti a c trong b tng thu c mt mu i din, nhng phi nh khi lng mi ln xc d dng thao tc bng tay.

5 LY MU 5.1 Cch ly mu hin trng - i vi b tng ly mu ngay ti hin trng, mu th nghim c ly theo phng php qui nh trong tiu chun AS 1012.1.

5.2 Cch ly mu trong phng th nghim - i vi b tng ly mu trong phng th nghim, mu th nghim c ly theo phng php qui nh trong tiu chun AS 1012.2.

6 TRNH TTh nghim c thc hin nh sau:a) Phi m bo chc chn rng mt trong ca thng cha v khun hnh nn ct c lm sch, khng dnh b tng kh.b) Trc khi th nghim, phi dng vi m lm t mt trong ca thng cha v khun hnh nn ct.c) t thit b ln trn mt b mt vng chc, khng b nh hng ca cc rung ng. Phi chc chn rng mt bn (G) nm ngang. Kp cht thng hnh tr (A) vo mt bn rung (G) bng cc c tai hng (H). t khun (B) ng tm vi thng cha ri xoay i xoay li h thp phu b tng (D) nh v trn ming khun. Vn cht vt (F) sao cho khun khng b x dch trn y ca thng cha.d) b tng vo khun thnh 3 lp, mi lp cao khong 1/3 chiu cao ca khun, phi cn thn lng b tng ca lp trn cng sau khi m cht bng thanh m vn y trn ming khun. C mt mui b tng vo khun th dng mui ny dn u ming khun m bo b tng c phn b i xng u trong khun.e) Dng thanh m (phn u trn ca thanh m hng xung b tng) m 25 lt ln mi lp b tng. Ch m u khp mt ct ngang ca khun. i vi lp di cng, khi m phi hi nghing chy nn nh vo gn chu vi vng quanh khun v phi m xung tn y ca lp b tng. Cc lp pha trn th chc thanh m sao cho va chm xung lp b tng pha di n.Ch thch - Phi trnh chm qu mnh ln tm phng yf) Khi cho b tng vo m lp trn cng, phi thnh ng sau mi bt u m. Nu khi m thy b tng b st xung thp hn ming khun, th cho thm b tng vo lng b tng y trn ming khun.g) Sau khi lp trn cng c m cht th ni lng vt (F), xoay phu (D) chch ra 90o, sau li vn cht b c vt li. Dng dao bay gt bng lp b tng trn cng ngang bng vi mp khun. Phi ch trong qu trnh thao tc khng b khun b nng ln khi y ca thng cha. i vi mt vi loi b tng c th cn phi c thm b kp b xung (v d nh b ngm) kp cht quai ca khun vi quai ca thng cha, c bit khi xoay mu ra ngoi mt gc 90o. Phi cn thn loi b phn b tng d ri vi khi vo khun hoc khi san bng ming khun.h) Nhc khun ra khi hn hp b tng theo chiu thng ng:(i)Khi th nghim c thc hin ti hin trng th nhc cn ln ngay khi cn y b tng

(ii)Khi th nghim c thc hin ti phng th nghim th nhc cn ln sau khi trn 4 pht. Ch thch - i vi nhng nghin cu c bit th th nghim c thc hin sau khong thi gian khc vi 4 pht nh qui nh trn y. Phi hon thnh vic nhc cn ra khi mu trong vng 3 1 giy v khng c lm x dch ngang hay xon.Ch thch C th thu c thng tin b ch bng cch o st ca b tng sau khi tho khun.i) Ni lng vt (F) v xoay tay (N) v a trong sut vo v tr bn trn lp b tng hnh nn ct b ln. Ni lng inh c (O) v t t h a thy tinh trong sut cho n khi chm vo lp b tng.

j) Vn cht vt (F) v bt my rung, ng thi bm ng h bm giy. Quan st qua a trong sut s ln dn c khi hn hp b tng v a. k) Tip tc rung cho ti khi thy h xi mng ph kn ton b mt di ca a v b tng c m cht hon ton th tt ng h v tt my rung.Ch thch Th nghim ny nhy nhn bit c s khc nhau v tr s Vebe tng dn ln trong cc giai on hydrt ha ban u ca xi mng . Do mi th nghim nn tin hnh trong mt khong thi gian khng i sau khi cho nc trn vi cc vt liu.

7 TR S VEBE

Tr s Vebe l khong thi gian rung tnh bng giy v c bo co chnh xc ti 0.5 giy.

8 GHI KT QU a) c im ca b tng

b) V tr cng trnh hoc phng th nghim thc hin th nghimc) Ngy thng v thi gian th nghimd) Tr s Vebe

e) Thi gian t khi kt thc trn n khi tho trong khun.f) H tn ngi th nghimg) Ti liu tham kho ca tiu chun ny, tc l tiu chun AS 1012.3.3.

9 BO CO Trong trng hp cn chun b bo co, th bo co gm cc thng tin sau:a) c im ca b tng

b) Ngy thng v ni th nghimc) Tr s Vebe

d) Thi gian t khi kt thc trn n khi tho trong khun

e) Ti liu tham kho ca tiu chun ny, tc l AS 1012.3.3.

f) Khi c yu cu th ghi cc thng tin khc nh trnh by trong mc ghi kt qu (xem AS 1012.1).

Hnh 1 S my o st VEBE

(i vi cc kch thc, dung sai chi tit khc vi kch thc ny, xem mc 3.1)

Hnh 2 My o st VEBE

Tiu chun ny do y ban BD/42 son tho: Cc phng php th nghim b tng. Tiu chun ny c Hi ng tiu chun Australia ph chun ngy 10 thng 7 nm 1998, v pht hnh ngy 5 thng 9 nm 1998.

(a) Mt ct chi tit

X-X v Y-Y

(b) Mt ct v

phi cnh mt bn

(c) Mt ct v

phi cnh mt trc

My rung

(a) Khun hnh cn sau khi lp t

(b) Sau khi nhc khun ra v t a trong sut thc hin rung

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