常用的地基沉降計(jì)算方法匯總

1、6.3常用的地基沉降計(jì)算方法這里所講的地基沉降量是指地基最終沉降量，目前常用的計(jì)算方法有：彈性力學(xué)法、分層總和法、應(yīng)力面積法和考慮應(yīng)力歷史影響的沉降計(jì)算法。所謂最終沉降量是地基在荷載作用下沉降完全穩(wěn)定后的沉降量，要達(dá)到這一沉降量的時間取決于地基排水條件。對于砂土，施工結(jié)束后就可以完成；對于粘性土，少則幾年，多則十幾年、幾十年乃至更長時間。6.3.1 計(jì)算地基最終沉降量的彈性力學(xué)方法Boussinesq課題的位移解為依據(jù)P時，見圖6-5,表面位移w（x,y,（6-8）地基最終沉降量的彈性力學(xué)計(jì)算方法是以的。在彈性半空間表面作用著一個豎向集中力o）就是地基表面的沉降量s：P1-2s=二rE式中以一

2、地基土的泊松比；E地基土的彈性模量（或變形模量Eo）;f22x+y。對于局部荷載下的地基沉降，則可利用上式，根據(jù)疊加原理求得。如圖6-6所示，設(shè)荷載面積A內(nèi)N（己J）點(diǎn)處的分布荷載為p0（己，"），則該點(diǎn)微面積上的分布荷載可為集中力P=po（己J）d也”代替。于是，地面上與N點(diǎn)距離r=J（x"）2+（y-刃2的m（x,y）點(diǎn)的沉降s（x,y）,可由式（6-8）積分求得：12po(,)dds(x，y)=e22(6-9)E0a.(x-)(y-)(a)任意荷載面；(b)式中以一角點(diǎn)沉降影響系數(shù)，由下式確定:(6-10)1'c=一JT1Jm22mln()ln(m.m1)m(

3、6-11)式中m=l/b。矩形荷載面從式(6-9)可以看出，如果知道了應(yīng)力分布就可以求得沉降；反過來，若沉降已知又可以反算出應(yīng)力分布。對均布矩形荷載po(>=p0=常數(shù)，其角點(diǎn)C的沉降按上式積分的結(jié)果為：1一；2.s=cbpoEo利用式(6-10),以角點(diǎn)法易求得均布矩形荷載下地基表面任意點(diǎn)的沉降。例如矩形中心點(diǎn)的沉降是圖6-6(b)中的虛線劃分為四個相同小矩形的角點(diǎn)沉降之和，即1-'121-''2s=4c(b/2)po=0bp0(6-12)EoE。式中牝=2球一中心沉降影響系數(shù)。圖6-7局部荷載作用下的地面沉降（a）絕對柔性基礎(chǔ)；（b）絕對剛性基礎(chǔ)以上角點(diǎn)法的計(jì)

4、算結(jié)果和實(shí)踐經(jīng)驗(yàn)都表明，柔性荷載下地面的沉降不僅產(chǎn)生于荷載面范圍之內(nèi)，而且還影響到荷載面之外，沉降后的地面呈碟形，見圖6-7。但一般基礎(chǔ)都具有一定的抗彎剛度，因而沉降依基礎(chǔ)剛度的大小而趨于均勻。中心荷載作用下的基礎(chǔ)沉降可以近似地按絕對柔性基礎(chǔ)基底平均沉降計(jì)算，即s=s(x,y)dxdyAA式中A一基底面積，s（x,y）一點(diǎn)（x,y）處的基礎(chǔ)沉降。對于均布的矩形荷載，上式積分的結(jié)果為:一2hsmbpoE0(6-13)(6-14)式中m一平均沉降影響系數(shù)。s=E02-bp。(6-15)可將式（6-10）、式（6-12）、式（6-14）統(tǒng)一成為地基沉降的彈性力學(xué)公式的一般形式：式中b矩形基礎(chǔ)（荷載）

5、的寬度或圓形基礎(chǔ)（荷載）的直徑,仍一無量綱沉降影響系數(shù)，見表6-1。基礎(chǔ)形狀圓形方形矩形（l/b）基礎(chǔ)剛度1.01.52.03.04.05.06.07.08.09.010.1100.0柔0c0.640.560.680.770.890.981.051.111.161.201.241.272.00性與01.001.121.361.531.781.962.102.222.322.402.482.544.01基礎(chǔ)沉降影響系數(shù)切值表6-1基礎(chǔ)mm0.850.951.151.301.521.201.831.962.042.122.192.253.70剛性基礎(chǔ)0r0.790.881.081.221.441.

6、611.72-2.123.40剛性基礎(chǔ)承受偏心荷載時，沉降后基底為一傾斜面，基底形心處的沉降（即平均沉降）可按式（6-15）取缶=到計(jì)算，基底傾斜的彈性力學(xué)公式如下:J-J2Pe171:tan=6-圓形基礎(chǔ):(6-16a)矩形基礎(chǔ):taiUE0Peb3(6-16b)E0b3式中基礎(chǔ)傾斜角；P一基底豎向偏心荷載合力；e一偏心距；b一荷載偏心方向的矩形基底邊長或圓形基底直徑;K一計(jì)算矩形剛性基礎(chǔ)傾斜的無量綱系數(shù)，按l/b取值，如圖6-8,其中l(wèi)為矩形基底另一邊長。通常按式（6-15）計(jì)算的基礎(chǔ)最終沉降量是偏大的。這是由于彈性力學(xué)公式是按勻質(zhì)線性變形半空間的假設(shè)得到的，而實(shí)際上地基常常是非均質(zhì)的成層

7、土，即使是均質(zhì)的土層，其變形模量Eo一般隨深度而增大。因此，利用彈性力學(xué)公式計(jì)算沉降的問題，在于所用的E0值能否反映地基變形的真實(shí)情況。地基土層的Eo值，如能從已有建筑物的沉降觀測資料，以彈性力學(xué)公式反算求得，則這種數(shù)據(jù)是很有價值的。此外，彈性力學(xué)公式可用來計(jì)算地基的瞬時沉降，此時認(rèn)為地基土不產(chǎn)生體積變形，例如風(fēng)或其它短暫荷載作用下，構(gòu)筑物基礎(chǔ)的傾斜可按式(6-16)計(jì)算,Christian和注意式中的E0應(yīng)取為地基彈性模量，并取泊松比=0.5。在大多數(shù)實(shí)際問題中，土層的厚度是有限的，下臥堅(jiān)硬土層Carrier(1978)提出了計(jì)算有限厚土層上柔性基礎(chǔ)的平均沉降計(jì)算公式：s-21也E0(6-1

8、7)式中，出取決于基礎(chǔ)埋深和寬度之比D/b,國取決于地基土厚度H和基礎(chǔ)形狀。取泊松比卜=0.5時飛和匕如圖6-9所示。對于成層土地基，可利用疊加原理來計(jì)算地基平均沉降。式(6-17)主要用于估計(jì)飽和粘土地基的瞬時沉降，由于瞬時沉降是在不排水狀態(tài)下發(fā)生的，因此，適宜的泊松比卜應(yīng)取0.5,適應(yīng)的變形模量E0應(yīng)取不排水模量Eu。例題6-1某矩形基礎(chǔ)底面尺寸為4m>2m,其基底壓力p0=150kPa,埋深1m,地基土第一層為5m厚的粘土，不排水變形模量Eu=40MPa,第二層為8m厚的粘土，Eu=75MPa,其下為堅(jiān)硬土層。試估算基礎(chǔ)的瞬時沉降。解：D/b=0.5,查圖6-9,%=0.94考慮上

9、層粘土，H/b=4/2=2,l/b=2,具有Eu=40MPa查圖6-9,匕=0.602150a=0.940.60=4.23mm因此40考慮二層粘土均具有Eu=75MPaH/b=12/2=6,l/b=2,查圖6-9,=0.852150rtS2=0.940.85=3.20mm因此75考慮第一層木土，具有Eu=75MPa,則2150S3=0.940.6=2.26mm75因此，總的瞬時沉降為：s-siS2-S3=4.233.202.26=5.17mm6.3.2計(jì)算地基最終沉降量的分層總和法(一)一維壓縮課題在厚度為H的均勻土層上面施加連續(xù)均勻荷載p,見圖6-10a,這時土層只能在豎直方向發(fā)生壓縮變形，

10、而不可能有側(cè)向變形，這同側(cè)限壓縮試驗(yàn)中的情況基本一樣，屬一維壓縮問題。施加外荷載之前，土層中的自重應(yīng)力為圖6-10b中OBA;施加p之后，土層中引起的附加應(yīng)力分布為OCDA。對整個土層來說，施加外荷載前后存在于土層中的平均豎向應(yīng)力(a)(bl(c)圖6-10土層一維壓縮V分別為p1='H/2和p2=p1+p0從土的壓縮試驗(yàn)曲線(圖6-10c)可以看出，豎向應(yīng)力從p1增加到p2,將引起土的孔隙比從e1減小為e2。因此，可求得一維條件下土層的壓縮變形s與土的孔隙比e的變化之間存在如下關(guān)系:ei-e2s二H（6-18）6-18）也可改寫成:這就是土層一維壓縮變形量的基本計(jì)算公式。式（as(P

11、2-P1)H1e1a1e1PHas=A=mvA或1e1s二也或Es式中a壓縮系數(shù)；mv一體積壓縮系數(shù)；Es壓縮模量；H土層厚度；A附加應(yīng)力面積,A=pH。（二）沉降計(jì)算的分層總和法1基本原理分別計(jì)算基礎(chǔ)中心點(diǎn)下地基各分層土的壓縮變形量si,認(rèn)為基礎(chǔ)的平均沉降量s等于si的總和，即ns=、sii二式中n一計(jì)算深度范圍內(nèi)土的分層數(shù)。(6-19)(6-20)(6-21)圖6-11分層總和法沉降計(jì)算圖例(6-22)1ei計(jì)算時si,假設(shè)土層只發(fā)生豎向壓縮變形，沒有側(cè)向變形，因此可按式（6-18）式（6-21）中的任何一個公式進(jìn)行計(jì)算。2計(jì)算步驟1）選擇沉降計(jì)算剖面，在每一個剖面上選擇若干計(jì)算點(diǎn)。在計(jì)算

12、基底壓力和地基中附加應(yīng)力時，根據(jù)基礎(chǔ)的尺寸及所受荷載的性質(zhì)（中心受壓、偏心或傾斜等），求出基底壓力的大小和分布；再結(jié)合地基土層的性狀，選擇沉降計(jì)算點(diǎn)的位置。2）將地基分層。在分層時天然土層的交界面和地下水位面應(yīng)為分層面，同時在同一類土層中分層的厚度不宜過大。一般取分層厚hiG.4b或hi=12m,b為基礎(chǔ)寬度。3）求出計(jì)算點(diǎn)垂線上各分層層面處的豎向自重應(yīng)力*（應(yīng)從地面起算），并繪出它的分布曲線。4）求出計(jì)算點(diǎn)垂線上各分層層面處的豎向附加應(yīng)力燈z,并繪出它的分布曲線，取e=0.2d（中、低壓縮性土）或0.1=c（高壓縮性土）處的土層深度為沉降計(jì)算的土層深度。5）求出各分層的平均自重應(yīng)力二ci二z

13、i°ci和平均附加應(yīng)力0zi,見圖6-11:1,上，下、二（；=ci,二ci）21,上上下、二（'-zizi）2上式中,、上二zi、下仃4第i分層土上、下層面處的自重應(yīng)力;下仃zi第i分層土上、下層面處的附加應(yīng)力。6）計(jì)算各分層土的壓縮量Sio認(rèn)為各分層土都是在側(cè)限壓縮條件下壓力從P1=仃&增加到P2Rei+仃石所產(chǎn)生的變形量Si,可由式（6-18）式（6-21）中任一式計(jì)算。7）按式（6-22）計(jì)算基礎(chǔ)各點(diǎn)的沉降量?；A(chǔ)中點(diǎn)沉降量可視為基礎(chǔ)平均沉降量；根據(jù)基礎(chǔ)角點(diǎn)沉降差，可推算出基礎(chǔ)的傾斜。例題6-2某柱基礎(chǔ)，底面尺寸l沖=4>2m2,埋深d=1.5m。傳至基

14、礎(chǔ)頂面的豎向荷載N=1192KN,各土層計(jì)算指標(biāo)見例表6-1和例表6-2。試計(jì)算柱基礎(chǔ)最土層側(cè)限壓縮試驗(yàn)e卞曲線例表終沉降量。假定地下水位深dw=2m土層計(jì)算指標(biāo)例表6-16-2土層1(kN/m2)a(MPa1)Es(MPa)粘土19.50.394.5粉質(zhì)粘土19.80.335.1粉砂19.00.375.0粉土19.20.523.4解：基1氐平均壓力pPl十?G"MbG基底附加壓力p。:p(kPa)土層050100200粘土0.8200.7800.7600.740粉質(zhì)粘土0.7400.7200.7000.670粉砂0.8900.8600.8400.810粉土0.8500.8100.7

15、800.7401192.=+20M1.5=179kPa4M2p0=p_d=179-19.51.5=150kPa取水的重度九M0kN/m3,則有效重度10,基礎(chǔ)中心線下的自重應(yīng)力和附加應(yīng)力計(jì)算結(jié)果見例圖6-1。到粉砂層層底，az=14.4kPa<0.2<Tc=0.2x91.9=18.3kPa,因此，沉降計(jì)算深度取為H=2.0+4.0+1.5=7.5m,從基底起算的土層壓縮層厚度為Zn=7.5T.5=6.0m。例圖6-1土層自重應(yīng)力和附加應(yīng)力分布按hi4b=0.4>2=0.8m分層。h1=0.50m,h2h6=0.80m,h7=h8=0.75m。柱基礎(chǔ)最終沉降量計(jì)算結(jié)果如下：e1

16、-e2si一(二)ihi(1)按公式1+ei計(jì)算。各分層土沉降量計(jì)算程序例表6-3土層分層hi(m)p1i(kPa)e1iP2i(kPa)e2isi(mm)粘土0-10.5034.20.7995180.70.743915.45120.8042.90.7228165.90.680219.78粉質(zhì)粘土2W0.8050.80.7197136.60.689014.283汨0.8058.40.7166115.80.69539.934七0.8066.20.7135105.40.69847.055-60.8074.00.7104102.00.69945.146-80.7581.60.8474102.70.8

17、3923.337-80.7588.40.8446104.90.83852.48粉砂(3)按公式Esi計(jì)算因止匕，s=ISi=77.44mm土層分層hi(m)p1i(kPa)e1iozi(kPa)a(MPa1)si(mm)粘土0T0.5034.20.7995146.50.3915.85120.8042.90.7228123.018.852W0.8050.80.719785.813.17粉質(zhì)粘土3汨0.8058.40.716657.40.338.834七0.8066.20.713539.26.045-60.8074.00.710428.04.326-80.7581.60.847421.13.17粉

18、砂7-80.7588.40.844616.50.372.48例表6-4hi因止匕s=2si=72.44mm二zisi二/asi=()i：-zihi(2)按公式1+8計(jì)算各分層土沉降量計(jì)算程序146.5s=4.50.50(123.085.857.439.228.0)0.805.1月誓h近HE圖6-12應(yīng)力面積的概念任意7度z范圍內(nèi)的壓縮量為(見圖6-12):0.75(21.116.5)=16.2852.305.64=74.22mm5.06.3.3地基沉降量計(jì)算的應(yīng)力面積法建筑地基基礎(chǔ)設(shè)計(jì)規(guī)范所推薦的地基最終沉降量計(jì)算方法是另一種形式的分層總和法。該方法采用了“應(yīng)力面積”的概念，因而稱為應(yīng)力面積法

19、。(一)土層壓縮變形量As的計(jì)算及應(yīng)力面積的概念假設(shè)地基是均勻的，即土在側(cè)限條件下的壓縮模量Es不隨深度而變，則從基底至地基zs=0dz=1z.AF0二zdz=Es0Es(6-23)式中名一土的側(cè)限壓縮應(yīng)變，名=Qz/EA深度z范圍內(nèi)的附加應(yīng)力面積，s；zA=；：.-2dz。因?yàn)椤=Ksp0,積A為：Ks為基底下任意深度z處的附加應(yīng)力系數(shù)。因此，附加應(yīng)力面A=0二zdz=P00Ksdz(6-24)為便于計(jì)算,（6-23）改寫為:引入一個豎向平均附加應(yīng)力（面積）系數(shù)&=A/（poZ）。則式s二貯Es(6-25)式（6-25）就是以附加應(yīng)力面積等代值引出一個平均附加應(yīng)力系數(shù)表達(dá)的從基底至

20、任意深度z范圍內(nèi)地基沉降量的計(jì)算公式。由此可得成層地基沉降量的計(jì)算公式（見圖6-13):AiA1='、'(苗zi-:izi)-Esi(6-26)式中p0可zi和p0«izi和zi-1深度范圍內(nèi)豎向附加應(yīng)力面積Ai和Aiv的等因此,代值。用式（6-26）計(jì)算成層地基的沉降量，關(guān)鍵是確定豎向平均附加應(yīng)力系數(shù)由豎向平均附加應(yīng)力系數(shù)0的定義，均布荷載po作用于夕!形（2a>2b）土表，相對其形心，在坐標(biāo)（x,y）處，從土表到z深處，可導(dǎo)出&的解析式如下：其中/rp天然地面標(biāo)高圖6-13成層地基沉降計(jì)算的概念T(4)11zarctan,，丫,_,i女2Xi2Yi2

21、z2(X：Y；z2/)(X：Y；Yj)-XiIn:22222(XiYjzYj)(XiYjYj)-YjIn(Xi2Yj2z2-Xi)(Xi2Yj2-Xi)(Xi2Yj2z2Xi)(X：Yj2-Xi)j=intt，一，一八2（表小取2的整數(shù)部分）Xi=x(-1)'aY=y(-1)jb(6-27)(6-28a)(6-28b)為便于計(jì)算，均布矩形荷載角點(diǎn)下的反列于表6-2;利用式（6-24）也可以求出均布三角形荷載角點(diǎn)、圓形面積均布荷載中心點(diǎn)和周邊點(diǎn)下的0值，并列于表6-3至表6-5,以供查用。為了提高計(jì)算準(zhǔn)確度，地基沉降計(jì)算深度圍內(nèi)的計(jì)算沉降量s',尚須乘以一個沉降計(jì)算經(jīng)驗(yàn)系數(shù)風(fēng)。建

22、筑地基基礎(chǔ)設(shè)計(jì)規(guī)范規(guī)定吸的確定方法為：5s=sc/s（6-29）式中s無一利用地基沉降觀測資料推算的最終沉降量。各地區(qū)宜按實(shí)測資料制定適合于本地區(qū)各類土的外值，而建筑地基基礎(chǔ)設(shè)計(jì)規(guī)范提供了一個采用表值，見表6-6o綜上所述，建筑地基基礎(chǔ)設(shè)計(jì)規(guī)范推薦的地基最終沉降量s的計(jì)算公式如下:ns=：s"Po(:izi-)/Esii=1(6-30)式中，n地基沉降計(jì)算深度范圍內(nèi)所劃分的土層數(shù)l/bz/b1.01.21.41.61.82.02.42.83.23.64.05.010.C0.00.25000.25000.25000.25000.25000.25000.25000.25000.25000

23、.25000.25000.25000.2500.20.24960.24970.24970.24980.24980.24980.24980.24980.24980.24980.24980.24980.2490.40.24740.24790.24810.24830.24830.24840.24850.24850.24850.24850.24850.24850.2480.60.24230.24370.24440.24480.24510.24520.24540.24550.24550.24550.24550.24550.2450.80.23460.23720.23870.23950.24000.240

24、30.24070.24080.24090.24090.24100.24100.2411.00.22520.22910.23130.23260.23350.23400.23460.23490.23510.23520.23520.23530.2351.20.21490.21990.22290.22480.22600.22680.22780.22820.22850.22860.22870.22880.2281.40.20430.21020.21400.21640.21900.21910.22040.22110.22150.22170.22180.22200.2221.60.19390.20060.2

25、0490.20790.20990.21130.21300.21380.21430.21460.21480.21500.2151.80.18400.19120.19600.19940.20180.20340.20550.20660.20730.20770.20790.20820.2082.00.17460.18220.18750.19120.19380.19580.19820.19960.20040.20090.20120.20150.2012.20.16590.17370.17930.18330.18620.18830.19110.19270.19370.19430.19470.19520.1

26、952.40.15780.16570.17150.17570.17890.18120.18430.18620.18730.18800.18850.18900.1892.60.15030.15830.16420.16860.17190.17450.17790.17990.18120.18200.18250.18320.1832.80.14330.15140.15740.16190.16540.16800.17170.17390.17530.17630.17690.17770.1783.00.13690.14490.15100.15560.15920.16190.16580.16820.16980

27、.17080.17150.17250.1733.20.13100.13900.14500.14970.15330.15620.16020.16280.16450.16570.16640.16750.1683.40.12560.13340.13940.14410.14780.15080.15500.15770.15950.16070.16160.16280.1633.60.12050.12820.13420.13890.14270.14560.15000.15280.15480.15610.15700.15830.1593.80.11580.12340.12930.13400.13780.140

28、80.14520.14820.15020.15160.15260.15410.1554.00.11140.11890.12480.12940.13320.13620.14080.14380.14590.14740.14850.15000.1514.20.10730.11470.12050.12510.12890.13190.13650.13960.14180.14340.14450.14620.1474.40.10350.11070.11640.12100.12480.12790.13250.13570.13790.13960.14070.14250.1444.60.10000.10700.1

29、1270.11720.12090.12400.12870.13190.13420.13590.13710.13900.1414.80.09670.10360.10910.11360.11730.12040.12500.12830.13070.13240.13370.13570.137表6-2均布矩形荷載角點(diǎn)下的平均豎向附加應(yīng)力系數(shù)日z/bl/b1.01.21.41.61.82.02.42.83.23.64.05.010.05.00.09350.10030.10570.11020.11390.11690.12160.12490.12730.12910.13040.13250.1345.20.09

30、060.09720.10260.10700.11060.11360.11830.12170.12410.12590.12730.12950.1325.40.08780.09430.09960.10390.10750.11050.11520.11860.12110.12290.12430.12650.1295.60.08520.09160.09680.10100.10460.10760.11220.11560.11810.12000.12150.12380.1265.80.08280.08900.09410.09830.10180.10470.10940.11280.11530.11720.11

31、870.12110.1246.00.08050.08660.09160.09570.09910.10210.10670.11010.11260.11460.11610.11850.1216.20.07830.08420.08910.09320.09660.09950.10410.10750.11010.11200.11360.11610.1196.40.07620.08200.08690.09090.09420.09710.10160.10500.10760.10960.11110.11370.1176.60.07420.07990.08470.08860.09190.09480.09930.

32、10270.10530.10730.10880.11140.1146.80.07230.07790.08260.08650.08980.09260.09700.10040.10300.10500.10660.10920.1127.00.07050.07610.08060.08440.08770.09040.09490.09820.10080.10280.10440.10710.1107.20.06880.07420.07870.08250.08570.08840.09280.09620.09870.10080.10230.10510.1097.40.06720.07250.07690.0806

33、0.08380.08650.09080.09420.09670.09880.10040.10310.1077.60.06560.07090.07520.07890.08200.08460.08890.09220.09480.09680.09840.10120.1057.80.06420.06930.07360.07710.08020.08280.08710.09040.09290.09500.09660.09940.1038.00.06270.06780.07200.07550.07850.08110.08530.08860.09120.09320.09480.09760.1028.20.06

34、140.06630.07050.07390.07690.07950.08370.08690.08940.09140.09310.09590.1008.40.0601.06490.06900.07240.07540.07790.08200.08520.08780.09890.09140.09430.0988.60.05880.06360.06760.07100.07390.07640.08050.08360.08620.08820.08980.09270.0978.80.05760.06230.06630.06960.07240.07490.07900.08210.08460.08660.088

35、20.09120.9519.20.05540.05990.096370.06970.07210.07610.07920.08170.08370.08530.08820.08130.0939.60.05330.05770.06140.06720.06960.07340.07650.07890.08090.08250.08550.07380.09010.00.05140.05560.05920.06490.06720.07100.07390.07630.07830.07990.08290.07190.08810.40.04960.05370.05720.06270.06490.06860.0716

36、0.07390.07590.07750.08040.06820.08510.80.04790.05190.05530.06060.06280.06640.06930.07170.07360.07510.07810.06490.08311.20.04630.05020.05350.05630.05870.06090.06440.06720.06950.07140.07300.07590.08111.60.04480.04860.05180.05450.05690.05900.06250.06520.06750.06940.07090.07380.07912.00.04350.04710.0502

37、0.05290.05520.05730.06060.06340.06560.06740.06900.07190.07712.80.04090.04440.04740.04990.05210.05410.05730.05990.06210.06390.06540.06820.07313.60.03870.04200.04480.04720.04930.05120.05430.05680.05890.06070.06210.06490.07014.40.03670.03980.04250.04480.04680.04860.05160.05400.05610.05770.05920.06190.0

38、67l/bz/b1.01.21.41.61.82.02.42.83.23.64.05.010.C15.20.03490.03790.04040.04260.04460.04630.04920.05150.05350.05510.05650.05920.06516.00.03320.03610.03850.04070.04250.04420.04690.04920.05110.05270.05400.05670.06218.00.02970.03230.03450.03640.03810.03960.04220.04420.04600.04750.04870.05120.05720.00.026

39、90.02930.03120.03300.03450.03590.03830.04020.04180.04320.04440.04680.052三角形分布的矩形荷載角點(diǎn)下的平均豎向附加應(yīng)力系數(shù)值表6-3l/b=0.2i/b=0.4l/b=0.6l/b=0.8l/b=1.0z/b角點(diǎn)1角點(diǎn)2角點(diǎn)1角點(diǎn)2角點(diǎn)1角點(diǎn)2角點(diǎn)1角點(diǎn)2角點(diǎn)1角點(diǎn)20.00.00000.25000.00000.25000.00000.25000.00000.25000.00000.25000.20.01120.21610.01400.23080.01480.23330.01510.23390.01520.23410.40.

40、01790.18100.02450.20840.02700.21530.02800.21750.02850.21840.60.02070.15050.03080.18510.03550.19660.03760.20110.03880.20300.80.02170.12770.03400.16400.04050.17870.04400.18520.04590.18831.00.02170.11040.03510.14610.04300.16240.04760.17040.05020.17461.20.02120.09700.03510.13120.04390.14800.04920.15710.

41、05250.16211.40.02040.08650.03440.11870.04360.13560.04950.14510.05340.15071.60.01950.07790.03330.10820.04270.12470.04900.13450.05330.14051.80.01860.07090.03210.09930.04150.11530.04800.12520.05250.13132.00.01780.06500.03080.09170.04010.10710.04670.11690.05130.12322.50.01570.05380.02760.07690.03650.090

42、80.04290.10000.04780.10633.00.01400.04580.02480.06610.03300.07860.03920.08710.04390.09315.00.00970.02890.01750.04240.02360.04760.02850.05760.03240.06247.00.00730.02110.01330.03110.01800.03520.02190.04270.02510.046510.00.00530.01500.00970.02220.01330.02530.01620.03080.01860.0336z/bl/b=1.2l/b=1.4l/b=1

43、.6l/b=1.8l/b=2.00.00.00000.25000.00000.25000.00000.25000.00000.25000.00000.25000.20.01530.23420.01530.23430.01530.23430.01530.23430.01530.23430.40.02880.21870.02890.21890.02900.21900.02900.21900.02900.2191z/bl/b=0.2i/b=0.4i/b=0.6i/b=0.8i/b=1.0角點(diǎn)1角點(diǎn)2角點(diǎn)1角點(diǎn)2角點(diǎn)1角點(diǎn)2角點(diǎn)1角點(diǎn)2角點(diǎn)1角點(diǎn)20.60.03940.20390.03970.2043

44、0.03990.20460.04000.20470.04010.20480.80.04700.18990.04760.19070.04800.19120.04820.19150.04830.19171.00.05180.17690.05280.17810.05340.17890.05380.17940.05400.17971.20.05460.16490.05600.16660.05680.16780.05740.16840.05770.16891.40.05590.15410.05750.15620.05860.15760.05940.15850.05990.15911.60.05610.14430.05800.14670.05940.14840.06030.14940.06090.15021.80.05560.13540.