單向分層總和法計算基礎中點最終沉降量案例

單向分層總和法計算基礎中點最終沉降量案例單向分層總和法計算基礎中點最終沉降量已知柱下單獨方形基礎，基礎底面尺寸為2.5×2.5m，埋深2m，作用于基礎上(設計地面標高處)的軸向荷載N=1250kN，有關地基勘察資料與基礎剖面詳見下圖。試用單向分層總和法計算基礎中點最終沉降量。解:按單向分層總和法計算(1)計算地基土的自重應力。z自基底標高起算。當z=0m，σ=19.5×2=39(kPa)sDz=1m，σ=39+19.5×1=58.5(kPa)sz1z=2m，σ=58.5+20×1=78.5(kPa)sz1z=3m，σ=78.5+20×1=98.5(kPa)sz1z=4m，σ=98.5+(20-10)×1=108.5(kPa)sz1z=5m，σ=108.5+(20-10)×1=118.5(kPa)sz1z=6m，σ=118.5+18.5×1=137(kPa)sz1z=7m，σ=137+18.5×1=155.5(kPa)sz13(2)基底壓力計算?；A底面以上，基礎與填土的混合容重取γ=20kN/m。0(3)基底附加壓力計算。(4)基礎中點下地基中豎向附加應力計算。用角點法計算，L/B=1，σ=4K?p，查附加應力系數(shù)表得K。zisi0si(5)確定沉降計算深度zn考慮第?層土壓縮性比第?層土大，經(jīng)計算后確定z=7m，見下表。n例題4-1計算表格1zzσσ/σzσzszzsznKs(m)B/2(kPa)(kPa)(%)(m)000.25002013910.80.1999160.758.521.60.112390.2978.532.40.064251.6298.843.20.040132.24108.529.7154.00.027021.71118.518.3264.80.019315.5213711.3375.60.014811.90155.57.6按7m計(6)計算基礎中點最終沉降量。利用勘察資料中的e-p曲線，求按單向分層總和法公式計算結果見下表。例題4-1計算表格2附加應力自重應力z平均值H平均值ee12(kPa)(kPa)(kPa)(cm)(m)(cm)-1(kPa)(kPa)(kPa)(cm)(kPa)03920110048.75180.85229.60.710.640.00038744184.09158.5160.710068.50125.501940.640.610.00023968611.835.92278.590.2910088.5070.96159.460.6350.620.00021177490.926.84398.551.62100103.541.93145.430.630.620.00023868480.617.454108.532.24100113.526.98140.480.630.620.00037143930.618.065118.521.71100127.518.62146.120.690.680.00053731470.598.65613715