GP29 Church Camp Landslide Church Camp GP29 ~250 m wide and ~200 m - - PowerPoint PPT Presentation

GP29 – Church Camp Landslide

Church Camp GP29

~250 m wide and ~200 m in length to the river Ponding water

Background

• The river valley is a pre-glacial valley with drift deposits to about 50m-

100m depth.

• It is unknown if the slide predated the highway possibly ancient deep

seated landslide.

• Highway was widened in 2013 for a new NBL likely constructed over

backscarp.

• Karl Engineering Consultants Ltd. Installed 3 Slope Inclinometers to

36 m and 3 piezometers

• Primary cause due to river erosion at the toe and high ground water

regime

Localized Landslides

2015 Lidar

Additional Geotechnical Investigation

• Drilled 9 test holes auger and wet rotary
• Three SIs installed to 51 m with 3 pneumatic piezometers to hopefully catch

deep seated movement

• Two SIs installed to 36 and 39 m deep with 2 pneumatic piezometers
• Three tests holes 6.6 m to 11.1 m deep with standpipes for re-alignment

information

6.6 m 6.6 m 11.1 m 6.6 m 36.1 m 51.4 m 51.2 m 51.4 m 39.2m

Gas Well Heads

Findings from Investigation

• 10
• 8
• 6
• 4
• 2

2 4 6 8 10 12 14/Aug/13 23/Sep/13 2/Nov/13 12/Dec/13 21/Jan/14 2/Mar/14 GROUNDWATER DEPTH (m) DATE FIGURE 17102 PIEZOMETRIC DEPTHS FOR HWY 2:70 11.8 km SOUTH OF RYCROFT

PN17-1A PN17-1B PN17-2A PN17-2B PN17-2C PN17-3B PN17-3C PN17-4A PN17-4B PN17-4C PN17-5A PN17-5B SP17-6 SP17-7 SP17-8 SP17-9

Ground Surface

PN17-3C PN17-3B PN17-4B PN17-4C Frozen

43 m (586.4 m elev.)

SI17-3

44.3 m (586.8 Elev.)

SI17-4

Wasn’t read in January because pneumatics were frozen and stuck inside

Karl’s old SIs

Remedial Measures

• Landslide is too large and deep for pile wall or toe berm
• Re-alignment of the highway is most cost effective option
• Well heads in farmers field will need to be taken into consideration
• WSP will be completing the re-alignment design

70 m Setback Bridge 110 m Setback Well heads