Report - Oregon State Library: State Employee Information Center ...

More documents

Recommendations

Info

Table 8.19: Deformation Results from Numerical Model Analyses with River Elevation at the Crest AEROPUERTO (0.12g) LONG VALLEY DAM (0.29g) Horizontal Vertical Horizontal Vertical DISPLACEMENT Displacement Displacement Displacement Displacement LOCATION (cm) (cm) (cm) (cm) Bottom of bench -0.7 -0.1 -2.0 -1.0 Top of bench -15.7 -1.0 -33.5 -2.0 North bottom of embankment -53.3 7.3 -55.6 3.1 North top of embankment -47.6 -49.3 -42.4 -54.4 South top of embankment 29.7 -11.9 38.5 -17.1 South bottom of embankment 38.3 11.7 50.2 18.0 Maximum for the embankment -82.4 -53.5 -79.3 -60.1 * Negative horizontal displacements represent movement toward the river and negative vertical displacements signify settlement. Two conclusions can be drawn from the results of the numerical modeling. First, the deformation of the levee gets progressively larger as the river elevation increases. As the river level increases, the phreatic surface also raises within the levee resulting in the saturation of more soil. These saturated soils are susceptible to excess pore pressure generation, resulting in larger levee deformations. Second, the deformations induced by the Long Valley Dam and Aeropuerto time histories are essentially the same for each river stage even though their respective PGA and duration values are significantly different. This indicates that the local shallow crustal earthquakes and subduction zone earthquakes are equally important for seismic hazard studies in this region. 8.9.4 Comparison of the Methods Four methods have been utilized to estimate the earthquake-induced deformations of the Columbia River levee. In general, the simplified procedures for estimating lateral displacements provide a range of values that can be very useful for preliminary hazard evaluations. However, the displacements estimated using the Makdisi and Seed method, the Bracketed Intensity method, and the numerical modeling-based design chart (Figure 7.8) provided a broad range of values, particularly for cases involving large magnitude earthquakes and very low stability (i.e., low values of k y /k max ). The limitations of the Makdisi and Seed methods for these conditions have been discussed in several references (Makdisi and Seed 1978; Jibson 1993). Table 8.20 presents a direct comparison between all of the methods using a M w 8.5 earthquake motion for the three river stages analyzed. This includes the Newmark, Makdisi and Seed, and Bracketed Intensity analyses that used the time history at elevation 6.4 m. Note that for the three sliding block based methods, the deformations correspond to the movement of the entire slide mass (rigid body movement). The deformation for the method developed from the parametric study represents the maximum deformation. The numerical model displacement is the horizontal displacement of the north top of the levee (embankment). 181
Table 8.20: Riverward Deformation Results Comparison for the Earthquake Magnitude 8.5 Analyses. METHOD OF CALCULATION RIVERWARD DISPLACEMENT: NORTH LEVEE CREST (cm) Low river stage Elev. NGVD 2.1 m 100 yr flood river stage Elev. NGVD 8.8 m Newmark 17 7 0 Makdisi and Seed 300 100 0 Bracketed Intensity 4 1 0 Results of the Parametric Study 40 30 1 Numerical Model 0 16 48 Levee crest river stage Elev. NGVD 13.0 m The direct comparison of the results of rigid-body, sliding block analyses with the results of the numerical model is complicated by two important issues; (1) the former methods focus only on the displacement of the slope along a single failure plane, and (2) benched slopes, like the riverside slope of the levee, should be evaluated for three different modes of failure (shallow crest, shallow bench, and deep-seated failure) when using limit equilibrium methods. In this example, the displacement values calculated from the rigid body analyses are only for failure wedges or circular slip planes associated with what was estimated to be a “critical” deep-seated riverward failure (Figure 8.24). The location and shape of the potential deep slip surface was established for the 100 year flood condition and this “critical circle” was used for the other two river stages. In slopes of cohesionless soils the critical circles are usually associated with shallow face and/or toe circles. The shallow failure modes were excluded from consideration in this example, as they were interpreted as indicating shallow sloughing. The displacements reported here did not take into account movement by other potential failure masses within the levee. The results of the Newmark and Bracketed Intensity methods show very little movement of the levee toward the river. This is in contrast to the results of the Makdisi and Seed method, which is considered to be very conservative for large magnitude earthquakes. Again, the critical failure surface indicated by the slope stability analysis for deep-seated riverward failures was used as the basis for the comparison. 20 Shallow Failure Surface 50 10 Elevation, NGVD (m) 0 -10 Deep Failure Surface 0 -50 Elevation, NGVD (ft) -20 -30 -100 Figure 8.24: Schematic Illustration of Shallow and Deep-seated Failure Surfaces. 182
Page 1:
ASSESSMENT AND MITIGATION OF LIQUEF
Page 5 and 6:
ACKNOWLEDGMENTS The authors would l
Page 7 and 8:
ASSESSMENT AND MITIGATION OF LIQUEF
Page 9 and 10:
8.0 HAZARD EVALUATION AND DEVELOPME
Page 11 and 12:
LIST OF FIGURES Figure 1.1: ODOT’
Page 13:
Figure 8.8: Long Valley Dam and Lak
Page 16 and 17:
Design of a given component shall l
Page 18 and 19:
Liquefaction Mitigation Procedure G
Page 20 and 21:
Pacific Northwest also are summariz
Page 23 and 24:
2.0 OVERVIEW OF LIQUEFACTION-INDUCE
Page 25 and 26:
oughly 50 centimeters, with numerou
Page 27 and 28:
supported bridges along the Seward
Page 29 and 30:
Another area of extensive bridge da
Page 31 and 32:
Nineteen bridges were also damaged
Page 33 and 34:
1. No foundation failures were obse
Page 35 and 36:
piles supporting the fourth pier, l
Page 37 and 38:
Figure 2.17: Observed Pile Deformat
Page 39 and 40:
Figure 2.19: Damage from the 1906 S
Page 41 and 42:
Figure 2.22: Ground Deformations Ne
Page 43 and 44:
induced ground displacement was the
Page 45 and 46:
Well-documented case histories of t
Page 47 and 48:
Similar damage to pile foundations
Page 49 and 50:
Examples of acceptable bridge found
Page 51 and 52:
Numerous investigations of liquefac
Page 53 and 54:
3.0 EVALUATION OF LIQUEFACTION SUSC
Page 55 and 56:
The evaluation of liquefaction haza
Page 57 and 58:
Table 3.1: Estimated Susceptibility
Page 59 and 60:
movements, or localized ground disp
Page 61 and 62:
Shear wave velocities can now be ob
Page 63 and 64:
3.4 LIQUEFACTION RESISTANCE: EMPIRI
Page 65 and 66:
Figure 3.1: Range of r d Values for
Page 67 and 68:
The earthquake-induced shearing str
Page 69 and 70:
drill rod during hammer impact. In
Page 71 and 72:
Figure 3.5: Minimum Values for K σ
Page 73 and 74:
3.4.2.2.1 CPT Method Developed by R
Page 75 and 76:
1. Sensitive, fine grained 6. Sands
Page 77 and 78:
Figure 3.9: CPT-Based Curves for Va
Page 79 and 80:
CRR where: q c 2 3 0.00128 0.0
Page 81 and 82:
Tacoma, Washington (Dickenson and B
Page 83 and 84:
Table 3.8: Influence of OCR on the
Page 85 and 86:
Figure 3.13: Influence of Fines Con
Page 87:
Gravel Sand Figure 3.16: Relationsh
Page 90 and 91:
FS L > 1.4: Excess pore pressure ge
Page 92 and 93:
The post-liquefaction strength of s
Page 94 and 95:
Figure 4.3: Undrained Critical Stre
Page 96 and 97:
4.3 INTRODUCTION TO MODES OF FAILUR
Page 98 and 99:
Figure 4.5: (a) Relationship betwee
Page 100 and 101:
not available for many case studies
Page 102 and 103:
provided to give the recommended ra
Page 104 and 105:
Figure 4.8: Overview of EPOLLS Mode
Page 106 and 107:
Figure 4.10: Model of Hypothetical
Page 108 and 109:
4.5.2 Advanced Numerical Modeling o
Page 110 and 111:
Figure 4.12: Post Volumetric Shear
Page 112 and 113:
The relationship shown in Figure 4.
Page 114 and 115:
A third type of failure is shown in
Page 116 and 117:
Table 5.1: Liquefaction Remediation
Page 118 and 119:
5.3 DESIGN OF SOIL MITIGATION The d
Page 120 and 121:
soil improvement guidelines state t
Page 122 and 123:
The models were instrumented with a
Page 124 and 125:
The model uses an explicit method,
Page 126 and 127:
A simplification was made in the mo
Page 128 and 129:
permanent earthquake displacements)
Page 130 and 131:
7.0 DEFORMATION ANALYSIS OF EMBANKM
Page 132 and 133:
engineers; (2) requisite input incl
Page 134 and 135:
π g 2 a t I a 2 dt (7-1) The A
Page 136 and 137:
10 1 Bracketed Intensity (m/s) 0.1
Page 138 and 139:
7.3 PARAMETRIC STUDY A well-validat
Page 140 and 141:
the rigid body methods. The point a
Page 142 and 143:
0.4 Acceleration (g) 0.2 0 -0.2 -0.
Page 144 and 145: Embankment Height (m) Depth of Liqu
Page 146 and 147: 10 1 DISPLACEMENT (m) 0.1 Morgan Hi
Page 148 and 149: 2.0 Embankment Toe Embankment Mid-S
Page 150: suitably reliable estimates of perm
Page 153 and 154: interest. Specifically, the peak be
Page 155 and 156: Flow Chart for Evaluation and Mitig
Page 157 and 158: The deformation evaluations were pe
Page 159 and 160: Portland (a) (b) Figure 8.2: Illust
Page 161 and 162: Figure 8.4: Contours of PGA on Rock
Page 163 and 164: Borehole 4E CPT Hole 4E 26.0' NGVD
Page 165 and 166: 8.4.2 Subduction Zone Bedrock Motio
Page 167 and 168: 154 Table 8.5: Selected Acceleratio
Page 169 and 170: Spectral Acceleration (g) 1.50 1.40
Page 171 and 172: with the calculated equivalent unif
Page 173 and 174: n ( M 10 1) (8-1) where M is the
Page 175 and 176: 0.20 0.15 0.10 Acceleration (g) 0.0
Page 177 and 178: 15.0 12.5 10.0 Long Valley Dam Lake
Page 179 and 180: CSR should be modified for the pres
Page 181 and 182: 8.7 EVALUATION OF INITIATION OF LIQ
Page 183 and 184: crest stage Marine Drive 42.5 ft NG
Page 185 and 186: Table 8.9: Fines Content Values Est
Page 187 and 188: large sliding and long-term disrupt
Page 189 and 190: Table 8.12: Deformation Results fro
Page 191 and 192: The earthquake time histories used
Page 193: North (river) South (land) North To
Page 197 and 198: applications (DDC, closely spaced v
Page 199 and 200: Table 8.21: Comparison of Predicted
Page 202 and 203: 9.0 SUMMARY AND CONCLUSIONS Recent
Page 204: dewatering may be warranted. Additi
Page 207 and 208: Bardet, J.P. (1990). “LINOS - A N
Page 209 and 210: California Division of Mines and Ge
Page 211 and 212: Fujii, S., M. Cubrinovski, K. Tokim
Page 213 and 214: Ishihara, K. and M. Cubrinovski. (1
Page 215 and 216: Liu, A.H. and J.P. Stewart. (1999).
Page 217 and 218: Oregon Department of Transportation
Page 219 and 220: Schnabel, P., J. Lysmer, and H.B. S
Page 221 and 222: Sun, I.H. and I.M. Idriss. (1992).
Page 223: Youd, T.L. and C.F. Jones. (1993).
show all

Report - Oregon State Library: State Employee Information Center ...

Create successful ePaper yourself

Delete template?

Save as template?