Galian 1TUGAS 3 METODE NUMERIK DALAM GEOTEKNIKEXAMPLE 14.3 (Muni Budhu)Flow Net dengan Metode Finite DifferenceAlbert Wilson Pardamean201410066596401

Tentukan laju aliran air di bawah dinding sheet pile dan distribusi tekanan air porinya menggunakan metode finite difference!

Diketahui:H1=4mH2=1mH=3mH3=6mD=12mGrid=1mk=0.0002cm/s

Penyelesaian:

Perhitungan dilakukan untuk area kiri saja karena aliran air pori dari kiri dan kanan adalah simetris

1.MENENTUKAN GARIS EKUIPOTENSIAL-kondisi batas-head pada batas ekuipotensialAB dan CD = garis ekuipotensialsepanjang AB, perbedaan head = 4 - 1 = 3BC, AE, dan DE = garis aliransepanjang CD, perbedaan head = 3/2 = 1,5 m

-memasukkan nilai head 3 pada sel A0 - Y0 (batas ekuipotensial AB) dan nilai head 1,5 pada sel Y6 - Y12 (batas ekuipotensial CD)

-dengan rumus berikut, menentukan head pada setiap sel dengan melihat batas impermeable-nya1pertama sekali menghitung head pada sel A1 dengan rumus 1 lalu drag sel ke bawah2pada sel A12, head dihitung dengan rumus 23untuk sel X12 dan Y5, menghitung head dengan rumus 1, lalu drag sel pada sel dengan kondisi yang sama4sel lainnya yang kondisi batasnya permeable, head dihitung dengan rumus 3

rumus 1rumus 2rumus 3

2

ABCDEFGHIJKLMNOPQRSTUVWXYEquipotentialz/x012345678910111213141516171819202122232403.003.003.003.003.003.003.003.003.003.003.003.003.003.003.003.003.003.003.003.003.003.003.003.003.0012.982.982.982.982.982.982.982.972.972.972.962.962.952.952.942.932.922.912.902.892.882.862.852.842.8422.962.962.962.962.962.952.952.952.942.932.932.922.912.892.882.872.852.832.802.782.752.722.702.682.6732.952.942.942.942.942.932.932.922.912.902.892.882.862.842.822.802.772.742.712.672.632.582.542.502.4942.932.932.932.922.922.912.912.902.892.872.862.842.822.802.772.742.702.662.622.562.512.442.372.312.2752.912.912.912.912.902.892.882.872.862.852.832.812.782.752.722.682.642.592.532.472.392.302.202.081.9862.902.902.902.892.882.882.872.852.842.822.802.772.752.712.682.632.582.522.462.382.292.182.041.841.5072.892.892.882.882.872.862.852.842.822.802.772.752.722.682.642.592.532.472.392.312.202.081.931.741.5082.882.882.872.872.862.852.842.822.802.782.752.722.692.652.602.552.492.422.342.252.142.011.871.691.5092.872.872.862.862.852.842.832.812.792.772.742.712.672.632.582.522.462.382.302.202.091.971.831.671.50102.862.862.862.852.842.832.822.802.782.752.732.692.652.612.562.502.432.362.272.172.061.941.801.651.50112.862.862.852.852.842.832.812.792.772.752.722.682.652.602.552.492.422.342.252.162.051.921.791.651.50122.862.862.852.852.842.832.812.792.772.752.722.682.642.602.542.482.422.342.252.152.041.921.791.641.502.MENENTUKAN TEKANAN AIR PORItekanan air pori dapat dihitung dengan rumus berikut:laju aliran per unit permeabilitas=(B58-B63+Z58-Z63+2*(SUM(C58:Y58))-2*SUM(C63:Y63))/4q'3.8987066747m3/sdenganw = 9,8 kN/m3laju aliran1nilai hi,j merupakan head ekuipotensial q0.0000077974m/s2contoh untuk sel B1, tekanan air pori = 9,8*(2,98+1) = 48,82 kPacontoh untuk sel A12, tekanan air pori = 9,8*(2.86+13) = 155,40 kPaABCDEFGHIJKLMNOPQRSTUVWXYPore Water Pressurez/x0123456789101112131415161718192021222324039.2039.2039.2039.2039.2039.2039.2039.2039.2039.2039.2039.2039.2039.2039.2039.2039.2039.2039.2039.2039.2039.2039.2039.2039.20148.8248.8248.8148.8048.7948.7848.7648.7348.7148.6748.6448.5948.5448.4848.4148.3348.2548.1448.0347.9147.7847.6547.5347.4547.41258.4458.4358.4258.4158.3958.3658.3258.2758.2258.1558.0857.9957.8957.7757.6457.4857.3057.1056.8856.6356.3656.0855.8355.6455.56368.0668.0668.0468.0267.9967.9467.8967.8267.7467.6567.5367.4067.2567.0866.8866.6566.3866.0865.7465.3664.9464.5064.0763.7263.56477.7077.6977.6777.6477.6077.5477.4777.3877.2877.1577.0176.8476.6476.4176.1575.8575.5075.1074.6574.1373.5572.9072.2271.6071.25587.3587.3487.3287.2887.2387.1687.0786.9686.8386.6886.5086.3086.0685.7885.4685.0984.6784.1883.6282.9782.2281.3480.3379.2078.24697.0197.0096.9796.9396.8796.7996.6996.5696.4196.2496.0395.7995.5195.1994.8294.3993.9093.3392.6891.9191.0189.9388.5586.6383.307106.69106.68106.65106.60106.53106.44106.33106.19106.02105.82105.59105.32105.01104.65104.24103.76103.21102.58101.84100.9999.9998.7997.3295.4693.108116.39116.38116.34116.29116.22116.12115.99115.84115.66115.44115.19114.90114.56114.17113.71113.20112.60111.92111.13110.22109.16107.93106.49104.80102.909126.10126.09126.06126.00125.92125.82125.69125.52125.33125.10124.83124.52124.16123.74123.26122.71122.08121.36120.53119.59118.51117.29115.90114.35112.7010135.85135.83135.80135.74135.66135.55135.41135.24135.04134.80134.52134.19133.81133.38132.88132.30131.65130.91130.06129.10128.01126.80125.46124.01122.5011145.61145.60145.56145.50145.42145.30145.16144.99144.78144.53144.24143.91143.52143.08142.57141.98141.31140.55139.69138.73137.64136.44135.14133.74132.3012155.40155.39155.35155.29155.20155.09154.94154.77154.56154.31154.02153.68153.29152.84152.33151.74151.07150.30149.44148.47147.39146.19144.90143.52142.1033.MENENTUKAN GARIS ALIRAN-head pada batas aliran1head pada sel A0 - A12 dan B12 - Y12 merupakan nilai q' per unit permeabilitas 2sepanjang BC nilai head aliran = 03semua nilai head tiap sel ditentukan dengan rumus 1 dan 3sel B0 - X0 dan Y7 - Y11 menggunakan rumus head 1sel lainnya menggunakan rumus head 3ABCDEFGHIJKLMNOPQRSTUVWXYFlowz/x012345678910111213141516171819202122232403.903.853.803.753.693.643.583.513.433.353.263.163.042.912.772.602.422.211.981.711.421.100.750.380.0013.903.853.803.753.703.643.583.513.443.363.273.163.052.922.782.612.432.221.991.731.431.110.760.390.0023.903.853.803.753.703.653.593.523.453.373.283.183.072.952.812.652.472.262.031.771.481.150.790.410.0033.903.853.813.763.713.663.603.543.473.393.313.213.112.992.852.702.532.332.101.851.561.230.860.440.0043.903.863.813.773.723.673.623.563.503.423.353.263.163.042.922.772.612.422.211.961.681.350.960.510.0053.903.863.823.783.743.693.643.593.533.463.393.313.223.113.002.862.712.542.342.111.841.521.130.630.0063.903.863.833.793.753.713.673.623.573.513.453.373.293.203.092.982.842.692.512.302.061.771.400.890.0073.903.873.843.813.773.743.703.663.623.563.513.453.383.303.213.102.992.852.702.532.322.091.821.521.2683.903.873.853.823.803.773.743.703.673.623.583.533.473.403.333.253.153.042.922.782.622.452.272.102.0193.903.883.863.843.823.803.773.753.723.693.653.613.573.523.463.403.333.243.153.052.942.822.702.612.57103.903.893.873.863.853.833.813.803.783.763.733.713.683.643.603.563.513.463.403.333.263.183.113.063.04113.903.893.893.883.873.863.863.853.843.833.823.803.793.773.753.733.703.683.653.613.583.543.513.493.48123.903.903.903.903.903.903.903.903.903.903.903.903.903.903.903.903.903.903.903.903.903.903.903.903.90

2423222120191817161514131211109876543210