^ ^ KHOA HOC VA C6NG NGHE MO DjNH KHOANG CACH HOP LY GlifA CAC L6 M I N CANH NHAU DANG LOfrl HINH CHUT NHAT TRiN GirONG THI CONG CONG T R I N H N G R M N/ NGHIEN CUU XAC GS.TS VO TRONG HUNG Trifong B^i hgc Mo-Dja chit ^ hoang c^ch giOa cac l5 hp'p IJ Id mOt j ^ thdng s6 k^ thuĐt-c6ng ngh^ quan ã^ ^ qud trinh khoan n6 khu vyc gu-ang thi c6ng cdng trinh ng4m Tuy nhifen cho d4n nay, v§n dk ndy vin chua du-Q-c nghidn ci>u th^u dao Nhilu nOi dung eg t h i tgi ddy van mang tinh djnh ttnh ma h6, thilu ^inh lu'O'ng [4], [5] Mdi quan h$ glCra cdc vung "dl^n tich don vj phd huy" va vung pha huy ddt da xung quanh cho mdi mpt id tren gu'o-ng thi cdng cdng trinh ngiim Vung "di$n tich dan vi phd huy" Id vCing di^n tich khdi dd trdn gu'ang thi cdng cdng trinh nglm dug-c thilt k l d l m5i l6 phai cd kha ndng phd hOy theo ydu ciu sau khoan nS tiln gu'ang Hinh dgng, kich thu-d-c cua cdc vOng "di$n tich dan vj phd huy" rit khdc thu$c vdo vj b*! eg thi cua Chung trdn gu-ang thi cdng cdng trinh nglm [5] Trdn l-i.1 md ta cdc sa d l ve mli quan h$ giOa cdc vCing "di^n tich dan vj phd huy" "A" vd vCing \'j thuylt phd huy d i t dd "2" xung quanh m6i mOt to trdn gu'ang thi cdng cdng trinh nglm: a - Sa d l hinh thdnh vDng ly thuylt phd huy dit dd xung quanh m6i l6 min; b - Sa dd moi quan h$ giOa vCing ly thuylt phd huy d i t dd xung quanh vd cdc vung "di^n tich dan vj phd huy" Tren thu'c t l , gid tri bdn kinh ly thuylt "R" cua vising phd hOy dat dd hinh trdn "2" (H.l.a) co t h i du'O'c xdc djnh theo mOt ly thuylt hodc kit qud thyc nghiem ndo dd H Cdc sa dd md ta m6i quan h$ giiia cic vung "di^n tich dan vj phd huy" va vOng phd hOy (Sit tfd xung quanh m0t 16 tren guong thi cdng cdng trinh ngim: b, c - Cdc kich thu^ vijng °di$n tich dan vj phd hOy" cda l5 T; - VCing /j? thuyit phd huy dit dd xung quanh Id T; - DwCrng biin vung ly thuyit phd huy dit dd xung quanh l6 7"; - Vung dit dd khong bj phd huy; - Dutmg bi§n vOng "di$n tich dan vi phd huy" cho m6i m^t l6 tr§n guxyng thi cong cdng trinh ngim Trong tru'd'ng hp'p ly tuang, sau bj kich n l m6i l6 dan dijc h-dn gu-ang se hinh thdnh m^t vDng dit dd phd huy cd dgng hinh h-dn cd dud-ng ^ CONG NGHIEP MO SO 1-2015 kinh "D" vd bdn kinh "R" (H.l.a) Gid trj cy the cua "D", "R" phg thudc vdo rit nhilu yiu t l vd di^gc xdc djnh bdng nhilu phuang phdp ly thuylt, thyc _J^ KHOA HOC VA CONG N G H | MO nghi$m, ly thuylt-thyc nghi$m khdc [4] VE dg, theo Repin N A [3], gid hi bdn kinh phd hiiy "R" cua c$t chit n l ddi (lu-g-ng nl) cd t h i xdc djnh theo cdng thi>c: R = (0.78.d^.l,.k).m (1) Tgi ddy: d - Dird'ng kinh cua c$t chit no ddi (lup'ng ni), m; It - Chiiu cao cOt chit n l , m; k - H$ so xdt din miic dd phd huy cua d i t dd; k=0,43-^0,40 tuang ung vdi mdi trudng dat dd khd n l ; k=0,46 (2R)>(bdVdc^0>{R.[V(2)]} tuang i>ng vdi mdi trudng dat dd cd muc dO kho nd frung binh B l thda man nhOng yeu cau t i i thilu ve hi0u qua can thilt cho cdng tdc khoan nd thi cdng cdng trinh nglm, tat ca cac chung logi hinh dgng, kich thudc cua cac vCing "di^n tich dan vj phd huy" cho mli mdt Id h-dn guang khdng dug-c vugj qud gid hi kich thudc vung ly thuyet phd huy cd the cua ddt da xung quanh cho mli mpt l6 h^dn guang ^ i cdng cdng h'inh nglm be=Ce={R.[V(2)]} - (bBvdCg)(2.R) ^ (2) dien hi^n tupng chIng lin sy tdc dgng cua sdng Trong trudng hpp ndy bin vung dit dd phd pha huy cd nguIn glc tCr hai Id cgnh nhau; huy "1" hinh thdnh sau kich n l cdc lo • Trudng hpp - Trudng hpp giCra edc l5 cgnh se hinh thdnh dOc Idp vdi khdng se hinh thdnh ding thdi vDng dit dd khdng bj phd chIng lin nhau, ndm cdch nhOng khoang huy (eye dd qud cd) kich thudc nhd "2" vCing dat edeh nhit djnh "di" (gida hai vdng lo min) vd "d2" dd bj phd huy " " vd edc viJng dit dd bj phd huy (giO-a hai 15 eiJng mOt vdng lo min): mgnh "3" {H.2.d) Khi dd, khoang cdch gida hai di=(b-2.R): d2=(c-2.R) (H.2.a) Khi dd frong vOng vdng l5 "b" vd khoang cdch gida hai l5 dit dd giua bin I I se tin tgi mpt khu vyc cung mpt vdng l6 "c" se thay ddi khdng bj phd huy "2" Ddy Id nguin glc cua logi dd khoang nhu sau: qud ed kich thudc rit Idn sau n l mtn; (2.R)>b>(R.^/2); (2.F^>C>(R.V2) (5) • Tnidng hpp - Trudng hpp giua cdc lo se hinh thdnh cdc viJng dit dd bj phd huy "1" vd Trong trudng hpp ndy, bin vCing dit dd phd huy vung dit dd khdng bi phd huy (cgc da qud ed) Idn "1" hinh thdnh sau kich n l cdc i l cgnh "2" (H.2.b) Khi do, khoang cdch giua hai vdng iS se chIng lin Idn (H.2.d) Khi dd, gida "bb" vd khoang cdch giua hai lo cCing cde lo se hinh thdnh ding thdi vCing dit dd mdt vdng iS "c" bdng nhau: khdng bj phd huy (dd qud cd) "2" vd bin vung ddt b=c=(2.R) ^ , (3) dd bj phd huy mgnh "3" Kich thudc vCing dat dd Trong trudng hpp ndy, bin viJng ddt dd pha huy khdng bj phd huy (dd qud cd) "2" nhd han trudng "1" hinh thdnh sau kich n l cde lo egnh hpp Ddy eung Id nguIn glc hinh thdnh cdc logi se hinh thdnh dpc l$p vdi nhau, tilp xCic vdi nhau, dd qua cd sau n l Tgi vung dit dd bj phd khdng chIng lan Idn (H.2.b) Khi dd, frong huy mgnh "3" se diln htdn tupng chIng lin sy vOng dit dd gida bin l6 se ton tgi mOt khu vyc tdc dgng cua sdng pha huy cd nguIn glc tu hai l3 dit dd khdng bj phd huy "2" Kich thudc cua viing egnh nhau; CONG NGHIEP MO S01-2015 _^^ KHDA HOC VA CfiNG NGHl MO •:• Trudng hpp - Truo'ng hpp gi&a cdc IS se hinh thdnh cac vDng dat dd bj phd hiiy manh "3" (H.2.e) Khi dfl, khoang cdch gida hai vflng 16 "b" vd khoang cdch giua hai |5 cung mpt vflng l5 "c" bdng nhau: b=c=(R.,/2) (6) Trong truflng hpp nay, cdc vCing dit da phd huy "1" hinh thdntijsau kich no cdc |6 nam canh (vCing x a y « hien tupng ching ilng suit phd huy gitta hai lo canh nhau) se chong lin len kich thufl'c io'n hon (H.2.e) Khi dfl, giua cdc 15 se hinh hai vCing dit dd bj phd huy vfl'i mile dfl ddp vo', phd huy dit dd tdng din tiiy theo mile dO tham gia tdc dflng cua hi§n tupng ching lin sing phd huy tir cdc |8 g i n nhau: VLing - VCing dit dd phd huy mjt lo kich n i gdy nfln; vCing - Vung dit dd phd huy msnh hai l5 kich n i gdy ndn Kieh thuflc vung dit dd bj phd huy manh "3" ion hon so v&i truflng hpp 3; •:• Tnrfl'ng hpp - Trufl'ng hpp giUa cdc lo se hinh bin viJng d i t dd bi phd huy "1", vOng dit dd bi phd huy manh "3", vung dit da b| phd huy rit manh "4", viing dit dd bi phd huy cue m^nh "5" (H.2.g) Khi do, khoang cdch giOa hai vong l5 "b" vd khoang each glita hai lo cung mOt vflng 15 "c" nho hon gid trj {R.[V(2)]}: b