深基坑悬臂式排桩支护的桩长及配筋设计

深基坑悬臂式排桩支护的桩长及配筋设计(,110036)(,110003)通过对深基坑悬臂桩支护特点的分析,介绍了桩的埋深受弯承载力桩间距截面配筋的计算方法,用工程实例论证了根据排桩的弯距图采用局部断面均匀配筋比上下一致的全断面均匀配筋更合理,可节约钢筋约48.5%左右深基坑悬臂式排桩受弯承载力配筋1,,,,,,,,1,,,,(),b,,b,,,,,c,(H.Blum)dc,12,8.5m,,;C20120cm,2425,,2.1桩的受力计算,q=20kN/m2,=18kN/m3,=30,C=19kN/m2,8m,!c1.22.1.1;Ka=tan2(45-/2)=0.3333Kp=tan2(45+/2)=3.0000Ea1=!c(q+rh1)ka-2cKa1/2=-13.94Ka/m2Ea2=!c(q+rh2)ka-2cKa1/2=47.26Ka/m22.1.2d!51!12du,U=kah/(kp-ka)=(0.3333∀8.5)#(3-0.3333)=1.06m22.1.3;E1=1/2∀47.26∀6.56=155.01kN/mE2=1/2∀47.26∀1.06=25.05kN/m∃P=E1+E2=180.06kN/ma.180.06a=155.01∀(2/3∀6.56+1.94)+25.0478∀(8.5+1/3∀1.06)a=6.67m∀Mc=0:∀p(l+x-a)-Epx/3=0x3-6∀p/r(kp-ka)x-6∀p(l-a)/r(kp-ka)=0x=5.81m1.2:t=u+1.2x=1.06+1.2∀5.81=8.032m,t=8m2.1.4:Q=0,OxmQ=0,∀p-r/2(kp-ka)xm=0Xm=[2Ep/r(kp-ka)]1/2=2.74m:Mmax=∀P(L+Xm-a)-r/6(kp-ka)Xm3=849.17kN2.1.5:;b=0.9(B+1)=0.9(1.2+1)=1.98m,2mMmax=849.17∀2=1698.34kN!m2.2排桩配筋,,,,,2.2.1;N%#cmA(1-sin2∃#/2%#)+(#-#t)yAsNei%2/3cmArsin3∃#/∃)+yAsrs(sin∃#+sin∃t)/∃#1=1.25-2#ei=e0+eaea=0.12[0.3(r+rs)-e0]A-;As-;r&;rs&;#&(rad)2∃&t-,#0.625,#=0#%0.625,#t=1.25-2#2.2.2;,,;N%#cmA(1-sin2∃#/2%#)+y(As∋r-As∋c-Asr-Asc)=0M%2/3cmArsin3∃#/#+yAsrrssin∃#s/%#s+yAsrrsc+yA∋srrssin∃#∋s/%#∋s+yA∋sry∋sc.(),1∋1200(KN.m)(:;:50mm)As(mm2)40006000800010000120001400016000180002000022000((%)0.350.530.710.881.061.241.411.591.771.95C20(kN.m)M163892812071478174119992252250127472989M2756113415121890226826463097346338254183M3789118315781972236627613246363040104387M4851127617012126256829603344371940864445:M1M2M3M4,M4,,As=7987mm2As=1/4∀7987=1997mm24!52!2004∋251963mm2As=3/4∀7987=5990mm212∋255890mm2(=7853/1130400=0.69;As,3/4As,120,1/4As,60,M4(3)39m(M4)2.2.3,,1/2Mmax,8mMmax=(1/2∀47.26∀6.56∀1/3∀6.56)∀2=677.92KN.m1/2Mmax=849.17KN.m(),;7.5m;2∋25,6∋259.0m;4∋25,12∋2524∋25,24∀16.5=396m,,7.5∀8+9∀16=204m,51.5%3,()(),,48.5%,,,,1.∗+.1999,2,.,∗+.20034,3,.∗+200310DesignofPileLengthandReinforcementofCantileverRowPileSupportsinDeepFoundationPitsAbstractThepaperpresentsmethodsofcalculatingthepileembedmentdepth,bendbearingcapacity,pilespacingandreinforcement,byastudyofcharacteristicsofcantileverrowpilesupportsindeepfoundationpits.Casesudiesareusedtodemonstratethatthemethodofthepartialsectionuniformreinforcementismorerationalandcosteffectivethanthatofthewholesectionuniformreinforcement,basedonthebendingmomentdiagramofrowpiles.Thenewmethodwillsavereinforcementbarsbyaround48.5%.KeywordsDeepfoundationpitCantileverRowpilesupportBendbearingcapacityReinforcement!53!12: