21 st Alert Workshop Program Aussois, October the 6 th 2010 Analysis of ground movements induced by diaphragm wall installation Benoit Garitte, Marcos Arroyo and Antonio Gens Universitat Politècnica de Catalunya, Barcelona
Rebaix de terres 20-8-08 21-7-08 21-6-08 22-5-08 Motivation Sant Cosme. Movimientos 1 T1B05282R289HT066Z T1B05283R207HT066Z T1B05286R207HT029Z T1B05294R208HT066Z Execució bigues centrals Estació Pas de la Tuneladora 12 10 8 6 4 Execució bigues c. Xuquer Jet 3 (1 col/2 dies) Jet 2 (<1 col/dia) Jet rampa (Jet 3) Jet protecció CC Pilots protecció Pantalles-pila (mòduls 92-95) Pantalles front CC (mòdul 76) Pantalles front CC (mòduls 71-75) Pantalles rampa costat edificis Pantalla rampa costat CC (mòduls R1-R5) -2 02-4 -10-8 -6-12 -14-16 -18-20 -22-24 -26-28 -30-32 -34-36 -38-40 -42-44 -46-48 -50-52 -54-56 -58 22-4-08 23-3-08 22-2-08 23-1-08 24-12-07 24-11-07 25-10-07 25-9-07 26-8-07 27-7-07 27-6-07 28-5-07 28-4-07 29-3-07 27-2-07 28-1-07 29-12-06 29-11-06 30-10-06 30-9-06 fechas asientos (mm) Settlements [mm] 58
Outline of the presentation Boundary condition for diaphragm wall: implementation and validation San Cosme station and parameter determination Modelling one panel: sensitivity analysis Modelling an entire diaphragm wall: comparison with in situ measurements Conclusions
Implementation of the boundary condition Literature review (Ng y Yan, 1998; Gourvenec & Powrie, 1999; Schaffer y Triantafyllidis, 2006) : Guide wall construction is not taken into account Excavation under bentonite slurry support is reproduced by retiring the elements included in the volume of the panel and applying the hydrostatic pressure (total stresses and null flux) Fresh concrete is reproduced by a bilinear hydrostatic boundary condition Hardening of concrete is reproduced by replacement of the panel volume by new elements with hard concrete parameters. The bilinear hydrostatic boundary condition is desactivated Installation Function: protection of existing structures Impermeabilization Stiffening
Implementation of the boundary condition Excavation under bentonite slurry Installation of fresh concrete Critical depth Gourvenec & Powrie, 1999
Implementation of the boundary condition Validation (2D): comparison between CB and G&P simulation results Profundidad [m] Depth [mm] 0-2 -4-6 -8-10 -12-14 -16-30 -25-20 -15-10 -5 0 Displacement [mm] Desplazamientos [mm] CB (bentonita) G&P (bentonita) CB (24h después bentonita) CB (hormigón) G&P (hormigón) CB (24h después hormigón)
Implementation of the boundary condition Gourvenec & Powrie, 1999 Displacement [mm] Installation of a panel is a 3D event Depth [mm] Effects due to the installation of various panels are not additive Correct representation of the earth pressure coefficient is a key issue
Outline of the presentation Implementation of the boundary condition in CB and validation San Cosme station and parameter determination Modelling one panel: sensitivity analysis Modelling an entire diaphragm wall and comparison with in situ measurements Conclusions
San Cosme station
San Cosme station and parameter determination Quaternary alluvial Silty clay Sand Clay Gravels
Parameter determination DMT (Marchetti Dilatometer)
Parameter determination DMT (Marchetti Dilatometer) Depth [m] 0.00-5.00-10.00-15.00-20.00-25.00-30.00-35.00-40.00-45.00-50.00 0.00 2.00 4.00 Id 6.00 8.00 Clay Arcill Silt Limo Sand Aren a DMT01 DMT02 DMT03 DMT04 Quaternary alluvial Silty clay Sand Clay Gravels
Parameter determination DMT (Marchetti Dilatometer) Depth [mm] Profundidad [m] 0.00-5.00-10.00-15.00-20.00-25.00-30.00-35.00-40.00-45.00-50.00 DMT01-1 DMT02-1 DMT03-1 DMT04-1 Ajuste del coefficiente de empuje 0.0 0.5 1.0 1.5 2.0 2.5 3.0 K 0 Horizontal stress index Earth pressure coefficient Quaternary alluvial Silty clay K 0 Sand σ ' = σ ' Clay Gravels h v
Parameter determination DMT (Marchetti Dilatometer) Depth [m] 0.00-5.00-10.00-15.00-20.00-25.00-30.00-35.00-40.00-45.00-50.00 Quaternary alluvial DMT01 DMT02 DMT03 DMT04 Gravels 0 200 400 600 E [bar] 800 1000 Silty clay Sand Clay DMT modulus Oedometer modulus λ (CC): 0.06
Parameter determination DMT (Marchetti Dilatometer) Depth [m] 0.00-5.00-10.00-15.00-20.00-25.00-30.00-35.00-40.00-45.00-50.00 0.00 1.00 2.00 3.00 OCR Preconsolidation pressure Swelling coefficient and friction angle: Mayne (2008): fitting of DMT and CPTu tests Permeability values were determined o the basis of in situ pump tests (AMPHOS)
Outline of the presentation Implementation of the boundary condition in CB and validation San Cosme station and parameter determination Modelling one panel: sensitivity analysis Modelling an entire diaphragm wall and comparison with in situ measurements Conclusions
Modelling one panel Modelling domain for one panel 50m 25m
Modelling one panel cota topográfica [m] Depth [mm] 0-5 -10-15 -20 Perfil hidrostático en la bentonita Perfil hidrostático en el hormigón Perfil en el hormigón (empírico) Tensión horizontal (total) -25 0 100 200 300 400 tensión [kpa] Stresses [kpa]
Modelling one panel Settlement evolution Settlement [mm] 1 0-1 -2-3 -4-5 Hardening of the concrete Injection of fresh concrete Excavation under bentonite support 0 10 20 30 40 Time [hrs] Settlement @ 2 m Settlement @ 3 m Settlement @ 4 m Settlement @ 5 m Settlement @ 10 m Settlement @ 16 m Di Biagio and Myrvoll, 1973
Modelling one panel Profundidad [m] Depth [mm] Convergence of the panel wall 0-5 -10-15 -20-25 t [horas] = 0.13, profundidad panel [m] = 1 t [horas] = 0.26, profundidad panel [m] = 2 t [horas] = 0.39, profundidad panel [m] = 3 t [horas] = 0.52, profundidad panel [m] = 4 t [horas] = 0.65, profundidad panel [m] = 5 t [horas] = 0.90, profundidad panel [m] = 7 t [horas] = 1.16, profundidad panel [m] = 9 t [horas] = 1.42, profundidad panel [m] = 11 t [horas] = 1.55, profundidad panel [m] = 12 t [horas] = 1.81, profundidad panel [m] = 14 t [horas] = 2.06, profundidad panel [m] = 16 t [horas] = 2.32, profundidad panel [m] = 18 t [horas] = 2.58, profundidad panel [m] = 20 t [horas] = 2.84, profundidad panel [m] = 22 t [horas] = 3.10, profundidad panel [m] = 24 t [horas] = 3.23, profundidad panel [m] = 25 t [horas] = 8.23, antes hormigonado Justo despues hormigonado t [horas] = 20.23, antes fraguado Justo despues fraguado t [horas] = 24 t [horas] = 2400-40 -20 0 20 40 desplazamientos [mm] Displacement [mm]
Modelling one panel Settlement profile Settlements asientos [mm] 2 0-2 -4-6 -8-10 -12-14 t [horas] = 0.13, profundidad panel [m] = 1 t [horas] = 0.26, profundidad panel [m] = 2 t [horas] = 0.39, profundidad panel [m] = 3 t [horas] = 0.52, profundidad panel [m] = 4 t [horas] = 0.65, profundidad panel [m] = 5 t [horas] = 0.90, profundidad panel [m] = 7 t [horas] = 1.16, profundidad panel [m] = 9 t [horas] = 1.42, profundidad panel [m] = 11 t [horas] = 1.55, profundidad panel [m] = 12 t [horas] = 1.81, profundidad panel [m] = 14 t [horas] = 2.06, profundidad panel [m] = 16 t [horas] = 2.32, profundidad panel [m] = 18 t [horas] = 2.58, profundidad panel [m] = 20 t [horas] = 2.84, profundidad panel [m] = 22 t [horas] = 3.10, profundidad panel [m] = 24 t [horas] = 3.23, profundidad panel [m] = 25 t [horas] = 8.23, antes hormigonado 0 10 20 30 40 50 Distancia hasta la pared [m] Distance to wall [m]
Modelling one panel: sensitivity analysis Case 1: base case Case 2: bentonite slurry level is 2m below the surface Case 3: length of the panel is 6m (instead of 3.6m) Case 4: depth of the panel is 35m (instead of 25m) Case 5: Critical depth is set to H/5 (instead of H/3) Case 6: width of the panel is 1m (instead of 1.2m) 1 Settlements [mm] asientos [mm] 0-1 -2-3 -4-5 Settlement evolution Asientos @ 3 m (caso 1) Asientos @ 3 m (caso 2) Asientos @ 3 m (caso 3) Asientos @ 3 m (caso 4) Asientos @ 3 m (caso 5) Asientos @ 3.1 m (caso 6) -6 0 10 20 30 40 Tiempo [hrs] Time [hrs]
Outline of the presentation Implementation of the boundary condition in CB and validation San Cosme station and parameter determination Modelling one panel: sensitivity analysis Modelling an entire diaphragm wall and comparison with in situ measurements Conclusions
Rebaix de terres Execució bigues centrals Estació Pas de la Tuneladora 20-8-08 21-7-08 21-6-08 22-5-08 22-4-08 23-3-08 22-2-08 23-1-08 Execució bigues c. Xuquer Jet 2 (<1 col/dia) 24-12-07 24-11-07 Modelling an entire diaphragm wall 12 10 8 6 4 Jet 3 (1 col/2 dies) Jet rampa (Jet 3) Jet protecció CC Pilots protecció Pantalles-pila (mòduls 92-95) Pantalles front CC (mòdul 76) Pantalles front CC (mòduls 71-75) Pantalles rampa costat edificis Pantalla rampa costat CC (mòduls R1-R5) -2 02-4 -10-8 -6-12 -14-16 -18-20 -22-24 -26-28 -30-32 -34-36 -38-40 -42-44 -46-48 -50-52 -54-56 -58 25-10-07 25-9-07 26-8-07 R1 p5 p7 p3 p6 p4 p2 p1 R2 R3 R4 R5 27-7-07 27-6-07 28-5-07 28-4-07 29-3-07 27-2-07 28-1-07 29-12-06 29-11-06 30-10-06 30-9-06 asientos (mm) Settlements [mm]
Modelling an entire diaphragm wall Settlements [mm] asientos [mm] 1 0-1 -2-3 -4-5 -6-7 Prisma 1 :3m desde panel (medidas) Prisma 2 :5.5m desde panel (medidas) Prisma 3 :13.5m desde panel (medidas) Prisma 4 :23.5m desde panel (medidas) Prisma 5 :31m desde panel (medidas) Prisma 6 :42.5m desde panel (medidas) Prisma 7 :49.5m desde panel (medidas) 15/11/2006 05/12/2006 25/12/2006 14/01/2007 03/02/2007 23/02/2007 R1 p3 p5 p7 R2 p2 p4 p6 R3 R4 p1 R5
Modelling an entire diaphragm wall
Modelling an entire diaphragm wall Settlement evolution 1 0 Asientos @ 3 m debidos a la ejecución de dos panel de 3.6m Asientos @ 3 m debidos a la ejecución de un panel de 6m Settlements [mm] asientos [mm] -1-2 -3-4 -5-6 0 50 100 Tiempo [horas] Time [hrs]
Modelling an entire diaphragm wall Settlement evolution 1 0-1 -2-3 -4-5 -6-7 Prisma 1 :3m desde panel (simulación) Prisma 1 :3m desde panel (medidas) Settlements [mm] asientos [mm] 15/11/2006 17/11/2006 19/11/2006 21/11/2006 23/11/2006 25/11/2006 27/11/2006 29/11/2006 01/12/2006 03/12/2006 05/12/2006 Di Biagio and Myrvoll, 1973
Modelling an entire diaphragm wall Settlement evolution 1 0-1 -2-3 -4-5 -6-7 Prisma 1 :3m desde panel (simulación) Prisma 1 :3m desde panel (medidas) Settlements [mm] asientos [mm] 15/11/2006 05/12/2006 25/12/2006 14/01/2007 03/02/2007 23/02/2007
Modelling an entire diaphragm wall Settlement evolution 1 Prisma 2 :5.5m desde panel (simulación) 0.5 0-0.5-1 -1.5-2 -2.5-3 Prisma 2 :5.5m desde panel (medidas) Settlements [mm] asientos [mm] 15/11/2006 17/11/2006 19/11/2006 21/11/2006 23/11/2006 25/11/2006 27/11/2006 29/11/2006 01/12/2006 03/12/2006 05/12/2006
Modelling an entire diaphragm wall Settlement evolution 1 0-1 -2-3 -4-5 Prisma 2 :5.5m desde panel (simulación) Prisma 2 :5.5m desde panel (medidas) asientos [mm] Settlements [mm] 15/11/2006 05/12/2006 25/12/2006 14/01/2007 03/02/2007 23/02/2007
Modelling an entire diaphragm wall Settlement profile Settlements [mm] asientos [mm] 1 0-1 -2-3 -4-5 -6-7 Simulación (R1-R2) @ 27/11/2006 Simulación (R4) @ 27/11/2006 Medida @ 12/02/2007 (p1) Medidas @ 12/02/2007 (otros prismas) 0 20 40 60 80 Distancia a la pared [m] Distance to wall [m]
Concluding remarks Diaphragm wall installation in soft soils may produce settlement in its neighbourhood. Numerical models may help to quantify and understand the problem. Three settlement phases were distinguished during the installation of a panel: Settlement during excavation under bentonite support Heave during injection of concrete Settlement during hardening of concrete Design parameters were classified by order of importance: The length of the panel The bentonite level during excavation The width of the panel The depth of the panel 3D effects were shown to be very important A good agreement between measured and simulated settlements was achieved Model limitations: soil-wall interface & concrete hardening
Implementation of the boundary condition Fresh concrete: Critical depth Schad et al., 2007 Lion Yard, Cambridge (Lings et al., 2004) H crit = H/3 H crit = H/5
Modelling one panel Case 1: base case Case 2: bentonite slurry level is 2m below the surface Case 3: length of the panel is 6m (instead of 3.6m) Case 4: depth of the panel is 35m (instead of 25m) Case 5: Critical depth is set to H/5 (instead of H/3) Case 6: width of the panel is 1m (instead of 1.2m) Settlements [mm] asientos [mm] 0-2 -4-6 -8-10 -12-14 -16-18 -20 Settlement profile t [horas] = 3.23 (caso 1) t [horas] = 3.23 (caso 2) t [horas] = 3.23 (caso 3) t [horas] = 4.35 (caso 4) t [horas] = 3.23 (caso 5) t [horas] = 3.23 (caso 6) 0 10 20 30 40 50 Distancia hasta la pared [m] Distance to wall [m] Profundidad [m] Depth [m] Convergence of the panel wall 0-5 t [horas] = 3.23, profundidad panel [m] = 25 (caso 1) t [horas] = 3.23, profundidad panel [m] = 25 (caso 2) -10 t [horas] = 3.23, profundidad panel [m] = 25 (caso 3) t [horas] = 4.35, profundidad panel [m] = 35 (caso 4) -15 t [horas] = 3.23, profundidad panel [m] = 25 (caso 5) t [horas] = 3.23, profundidad panel [m] = 25 (caso 6) -20-25 -40-30 -20-10 0 Desplazamiento Displacement [mm] [mm]