HomeMy WebLinkAboutCT 72-20; La Costa; Soils Report; 1971-05-23_-’ ” T. FUNNfiKOTTER ENGINEERING GEOLOGY GEOPHYSICAL INVESTIGAUONS PE‘ISTERED CEOtOGIsr FW
1 cwTlF,EO ENGINEERING GEOLOGIST S”bdi”i,iO” Design
P. 0. Box 575 . ESCONDIDO. CALIF. 92025 Pip.linn Roods
7.e.2793 sdmlic Ripp.abay Studis,
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La Ccsts Inc. San Xc:;0 County, Calif.
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ENGINEERING DEPT. LKJRARY
City of Carlsbad
2075 Las Palmas Drive
Catfsbad CA 92009-4859
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- T. FUNNEKOTTER ENGINEERING GEOLOGY - REGISTERED GEOLOGlST
CERTIFIED ENGlNEEPlNG GEOLOGIST
P. 0. BOX 575 ESCONDIDO, CALF. 02025
146.2793 -
GEOPHYSICAL INVESTlGATIONS
For
sutdivi,ion Design
Pipeline, - Rood‘
seimic Pippobility Studies
Purpose : To evaluate subsurface conditions at several select locations .-
in order to provide design and excavation information.
- Xethod : Refract& Seisnoqaphy. Geologic reconnaissance.
UiscGsion: All areas investigated are ur.derlain by the Black Kountain
Volcanics; however two areas indicate extensive low velocity
sandstone and/or siltstone. This report includes lines Al3 thru
H13, C13X1, and Cl3X2. Total Seisnic coverage is 3750 lineal feet.
Line Al3 indicates high velocity material from lit! feet to 28
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-. feet deep. Overlying this is low velocity depositional claterial
with velocities of 2300 to 2900 ft/sec. LirmBl3 is conposed of
Black Mountain Volcanics (BMV) with the high velocity material
appearing at depths of 22 feet to 40 feet. Line Cl3 is also E4V
- the high velocity naterial here varies in depth from 5 feet to
38 feet. The cross lines on Cl3 indicate similar conditions. The
southeast half of line D13, line E13, and line F13 all ifidicate
high velocity volcanics from 9 feet to 30 feet deep. On lim D13
from station 4.5 northwest, a different situation exists. Here
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the high velocity volcanics were not encountered. Rather, three
low to moderate velocity layers were mapped, i.e., 1300 ft/sec,
1800 to 2000 ft/sec, and 3400 to 4000 ft/sec. This situation
indicates that this particular area is, in part, depositional
in character. i~axirnxn Fenetration here is 45 feet deep. Lines G13
ar,d H13 are cornposed of BbIV with the harder high velocity material
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1.. - - T. FUNNEKOTTER - REGISTERED GEOLOGIST
CEPTIF~EO ENGINEERING GEOLOGIST
p 0. BOX 575 ESC0N0I00, CALIF. 92025
746.27P3 -
ENGINEERING GEOLOGY GEOPHMKAL INVESTlGATlONS
F-2,
S”bdi”ilion Design
Pipeli”” Roodr
sirmic *ipp.billty SwJic,
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Discussion: (can't) -
- 3% ds~ths or' l+ <23t to 28 feet deep. As usual, th3 pr33er.ce of
scattered blocks of hard volcanic naterial should be anticipated,
especially where noted on the velocity profile.
Conclusion: Virtually all lines investigated indicate a three layer profile
- - soil, decomposeti z.r,d fractured volcanics, and the parent, high
velocity volcmics. Two exceptions are noted - lice Al3 and north-
west half of D13 - both are, in part, depositional and conposed
- of softer sandstone and siltstone.
in terns of ri?pnbility, the follqfing schedule would aply:
- Velocity (ft/.;ec) Excavation Method
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0 to 2oco Scraper 2000 to 5000 Ripper 5000 to 5500 iCargina1 Over 5500 Drill EC Shoot
Submitted &ggT,T;:/L$$
1. Funnekotter