;Model to test establishment of a pp gradient, I impose different pp on each lateral boundary and no gravity ; results: pore pressure does not equillibrate immediately, but takes a very long time. in the model below, it takes approximately 120 nmech * 100 nflow to reach equillibrium, or alternatively, it takes 1100 nmech * 10 nflow to reach equil. as can be seen in the run dsich where the full crust breakes at disch1e8 which is 1100 steps after the start of discharge, but does not necessarily mean equilibrium, but that it is approaching it. In order to apply discharge I need to have means to set it up. tit FLAC Modelling Input File ; config extra 4 gw grid 100 100 gen 0.00e0,0.00e0 0.00e0,1.00e4 1.00e4,1.00e4 1.00e4,0.00e0 i=1,101 j=1,101 mark i=1 mark j=1 mark i = 101 mark j = 101 ; *************************************** model mohr water bulk 2e9 dens 1000 prop poro=0.3 ; to be elaborated below ;; 1 mech step = 1 fluid step; modify if necessary!!! ;set nmech off ngw 1 flow on *************************************** ; ; Properties for each sub-regions: pro dens= 2720 bulk=4.09e9 shear=2.45e9 pro coh=3.00e7 tens=1.50e7 pro fric=30 dil= 5 pro perm=1.00e-13 porosity=0.3 ; this sets stress everywhere to 2kb and gravity is zero ini sxx=-2e8 ini syy=-2e8 ini szz=-2e8 ini sxy=0e6 ; ; ;this sets initial pp everywhere (RW Santiago 2002) ini pp=1.e7 i=1 ini pp=0.0 i=101 ;pore pressure is fixed at each side at different levels, to see the establishment of a gradient fix pp i=1 fix pp i=101 ini sat 1 fix sat ; set gravity=0.0 ; fix x i=1 fix x i= 101 fix y j=1 fix y j=101 ; Schaubs: make sure to put these commands after the fish function which computes your initial stress hist 1 unbal nstep 1 ;set small ;set mech on fl off ;step 200 ;ini xd 0 yd 0 ;ini xvel 0 yvel 0 ;set mech on fl on ;step 200 ; this can be increased if you think the unbalanced forces haven't bottomed out ;ini xd 0 yd 0 ;ini xvel 0 yvel 0 ;pl hold hist 1 set large ;initial velocity command should be here ie ini xvel 0.004 etc; set mech off ;ini xvel 0.0000002 var=-0.0000004 ,0 i=1, 101 j=1, 101 ; ; result in one step, a smooth gradient is not established, there is a rapid exponential pp decrease at the high pressure side step 1 plot hold pp fill save t.sav ; ;ini xvel 0.02 var=-0.04 ,0 i=1, 101 j=1, 101 ;set nmech 1 ngw 10 flow on step 500 save t1.sav step 500 save t2.sav step 500 save t3.sav step 500 save t4.sav step 500 save t5.sav step 500 save t6.sav step 500 save t7.sav step 500 save t8.sav step 500 save t9.sav step 500 save t10.sav step 500 save t11.sav step 500 save t12.sav step 500 save t13.sav step 500 save t14.sav return stop