. Hinh 4-3 D~p hinh cong dcm giim
3. D{ip mijt cat hinh da giac( hinh thang)
D~p m~t c~t hinh da giac co du t(lo dan gian, thi cong dS nhung kha nang thao nuac qua d~p nhO, vi v~y chUng chi thuimg duQ'c sir d\ll1g cho d~p khong tran ho~c d~p triln thAp, quy mo nho.
- D~g a: Chi sir d\ll1gcho d~p tIlong d6i cao tra len va chi thucrng sir d\ll1g cho d~p khong tran.
- D~g b va c: C6 th~ sir d\lng cho d~p tran va ~p khongtran va chi thucrng sir d\ll1gcho d~p thdp.
Khi d~p la ~p khong tran, chi~u rQng 8 ClladiOO~p din cu vao di~u ki~n thi cong, giao thong tren rn~t d~p, di~u ki~n quan Iy d~ chQn.
Khi ~p la d~p tran, chi~u rQng 8 cua diOOd~p cAnchQn 006 d~ khong lam giam kha nling thao nucrc cua d~p.
H~ s6 luu luqng cua d~p : rn =0,32 +0,44 my vao chi~u cao d~p P, chi~u rQng dinh 8, dQxmUrnai d~p 81>82 (hinh 4-4), co th~ tra aph\ll\lc 9-1.
a) p b) P c) p \ i I
ffinh 4-4.M(>t 56d:!ng d~pm~t elit ngang blnhDa gilic
4.3. LVA CHQN cAu T~O CHO cAc DC) P~N CUA D~P TRAN
D~p tran co 3 b(l ph~n chiOOla : than cong triOO(than d~p), cira vao va cira ra. Trong rn6i b(l pMn h;1ig6rn OOi~ub(l ph~n khac (HiOO4-5). Ta se Ian luqt nghien CUutlrng b(l ph~.
4.3.1. Than cong trinh
1. Thana(ip
Than d~p co tac d\lng cM yeu la dang nucrc va thao nucrc qua d~p. Cao dQ diOOd~p khi khong b6 trl cira van, cira phai Idy biing MNDBT athuqng luu. Khi
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du t(lOrn~t c~t ngang d~p ta da nghien CUutrong rn\lC4.2.
V6i d~p Ian thucrng phili b6 trl ducrng hAm d~ quan Iy (d~ thao nucrc thdrn, quan tr~c thdm, quan Wc nUt...) trong than d~p.
Vi~c xac diOOkhAu di~n tran (chi~u rQng B va chi~u sau H cua rn~t c~t u6t khi
Baov~mai
7
2
10
~6
Kenh Cua vao
an nuae vao 3 ~I Than d~p ~8 Cua fa ~9 Kenh d n nuae fa H'mh 4-5. Cliu t(lo d~p tran
I. ThAn d~p; 2.M6ben; 3.M6gill'a; 4. CUa van; 5. Cllu giao tMng;
6. SAn tmac; 7.Titangeanh thl!ang; 8. SAn tieu nang; 9. SAn sau 2;