LIBRARY. «-*/ f ion a JUN 1 2 1997 !L (jcul. ourWEY ; QoJ> 2«AAX-W f&S: EGN 124 GEOLOGICAL-GEOTECHNICAL STUDIES FOR SITING THE SUPERCONDUCTING SUPER COLLIDER IN ILLINOIS: RESULTS OF DRILLING LARGE- DIAMETER TEST HOLES IN 1986 / \ / 3 S z^rf / / y s > ',',',',', ' ', ', ', / ',',',',',, / ^ / / / zrzzzrzzzzz zrzzzzzzzzz. ^/^ ^ * / / / / ^7 R. C. Vaiden / / / / s^r M. J. Hasek / ; ; / ; / / / / /^7 / / / / / y C. R. Gendron * ^ / / ^ 7 ' '. /. /. B. B. Curry - '.', ; / / / ^ — A. M. Graese / / s / s z 5^^ ^ ^ R. A. Bauer /7777 > v v y y -Mum 1988 iiUN 1 3 ENVIRONMENTAL GEOLOGY NOTES 124 ''l. STATE GEOiOfiMKiip Department of Energy and Natural Resources ILLINOIS STATE GEOLOGICAL SURVEY LIBRARY. Vaiden, Ft. C. Geological-geotechnical studies for siting the Superconducting Super Collider in Illinois: results of drilling large-diameter test holes in 1986/ by R. C. Vaiden ... et al.—Champaign, IL: Illinois State Geological Survey, 1988. 57 p.; 28 cm. — (Environmental Geology Notes; 124) Bibliography: p. 42-44. 1. Geology— Illinois—Kane County. 2. Geology— Illinois—DuPage County. 3. Hydrogeology— Illinois—Kane County. 4. Hydrogeol- ogy— Illinois—DuPage County. 5. Geophysical exploration— Illinois, Northeastern. 6. SSC. I. Title. II. Series. Printed by authority of the State of Illinois 1 1988 1 1500 ILLINOIS STATE GEOLOGICAL SURVEY 3 3051 00005 5016 GEOLOGICAL-GEOTECHNICAL STUDIES FOR SITING THE SUPERCONDUCTING SUPER COLLIDER IN ILLINOIS: RESULTS OF DRILLING LARGE- DIAMETER TEST HOLES IN 1986 ILLINOIS STATE GEOLOGICAL SURVEY Morris W. Leighton, Chief Natural Resources Building 61 5 East Peabody Drive Champaign, Illinois 61820 R. C. Vaiden M. J. Hasek C. R. Gendron B. B. Curry A. M. Graese R. A. Bauer 1988 ENVIRONMENTAL GEOLOGY NOTES 124 JUN13i U. STATE GEOLOSMI W' Digitized by the Internet Archive in 2012 with funding from University of Illinois Urbana-Champaign http://archive.org/details/geologicalgeotec124vaid CONTENTS EXECUTIVE SUMMARY v INTRODUCTION 1 GEOLOGIC SETTING 1 BEDROCK STRATIGRAPHY 4 Silurian System 4 Ordovician System 4 Cambrian System 5 GLACIAL DRIFT STRATIGRAPHY 5 DRILLING PROGRAM 6 GENERAL PROCEDURES 8 Sampling Procedures 9 Geophysical Logging 10 Videocamera Imaging 12 Groundwater Data 13 RESULTS 15 Geology 15 Hydrogeology 18 Spectral Gamma Ray Logs 22 Caliper Logs 22 Geotechnical Characteristics 25 TEST HOLES SSC-1 31 SSC-2 34 SSC-3 39 REFERENCES 42 APPENDIX A: Logs of Test Holes 45 APPENDIX B: Borehole Description from Closed Circuit Television 51 APPENDIX C: Geophysical Logging 55 TABLES 1 Location and approximate elevation for each test hole 7 2 Thickness of units penetrated in test hole 8 3 Characteristics of piezometers installed in each test hole 12 4 SSC observation well data (depth to water in feet below ground surface), monitored from April to December 1987 19 5 Water temperatures recorded after drilling 21 6 Laboratory logging of Rock Quality Designation (RQD) and fracture frequency of SSC-2 compared with values from adjacent Test Holes ISGS F-1, S-28, S-29 25 7 Discontinuity characterization for 4-inch core from Test Hole SSC-2 26 8 Strength and associated properties of 4-inch-diameter core from Test Hole SSC-2 27 9 Comparison of unconfined compressive strength of 4-inch and 1.8-inch cores 28 10 Average values for rock mass characteristics calculated from in situ sonic velocities 28 11 Comparison of field and laboratory compressive sonic velocities 29 FIGURES 1 Geologic map of the bedrock surface. 2 2 Stratigraphic column of bedrock and drift units in the study area north of the Sandwich Fault Zone in northeastern Illinois. 3 3 Location of all SSC drilling sites. 6 4 Comparison of selected geophysical logs from Test Hole SSC-1. 11 5 Generalized diagram of triple piezometer installation. 14 6 Concentrations of uranium (ppm) measured in geologic materials in SSC-1. 16 7 Comparison of piezometer levels with regional water levels. 20 8 Concentrations of total potassium (%) measured in geologic materials in SSC-1. 23 9 Concentrations of thorium (ppm) measured in geologic materials in SSC-1. 23 10 Stratigraphic correlations of spectral gamma ray records showing concentrations of total potassium (%), equivalent thorium (ppm), and equivalent uranium (ppm) for in situ measurements in three test holes. 24 11 Dip of fractures and joints in the Wise Lake Formation (Galena Group), Dunleith Formation (Galena Group), and Platteville Group. 29 12 Stratigraphic column of SSC-1. 32 13 Selected geophysical logs from SSC-1. 33 14 Stratigraphic column from SSC-2. 36 15 Selected geophysical logs from SSC-2. 37 16 Stratigraphic column from SSC-3. 40 17 Selected geophysical logs from SSC-3. 41 EXECUTIVE SUMMARY The Illinois State Geological Survey (ISGS) has completed an extensive four-year study of the area near Fermi National Accelerator Laboratory (Fermilab) at Batavia, 30 miles west of Chicago. This comprehensive investigation was conducted to locate the most suitable site for construction and operation of the Superconducting Super Collider (SSC)—a 20-trillion electron volt (TeV) subatomic particle accelerator. Illinois proposes to place the SSC below ground surface in a 10-foot-diameter tunnel about 53 miles in circumference. Underlying the proposed site in northeastern Illinois, between 250 and 600 feet deep, are the Galena and Platteville dolomites—strong, stable, nearly impermeable bedrock. To confirm that these bedrock units are suitable for construction of the SSC, ISGS geologists designed a four-year study including test drilling, rock sampling and analysis, geophysical logging, hydrogeologic studies, and seismic exploration. Initially, the study covered parts of six counties. Subsequent research focused on successively smaller areas until the final stage of test drilling in spring 1986 concentrated on a likely corridor for the SSC tunnel. From 1984 to 1986, thirty 3-inch-diameter test holes were drilled and more than 2 miles of bedrock core was recovered for stratigraphic description and geotechnical analysis. To supplement the information gained from the small-diameter holes, geologists drilled three 8-inch-diameter holes. The larger diameter of these holes allowed researchers to • use geophysical tools that are standard in the oil industry to (1) record sonic velocity data needed to generate synthetic seismic profiles, (2) acquire supporting data on rock properties, and (3) generate logs to compare with data recorded using ISGS equipment; • install piezometers at different elevations in each test hole; • extract representative 4-inch-diameter core samples for comparative rock strength tests; • conduct a pump test with standard equipment; • sample water during drilling; • record downhole features, structures, and possible water inflow with a videocamera. The primary purpose of drilling the 8-inch test holes was to collect geophysical data for use in interpreting seismic reflection profiles. Sonic logs and other downhole geophysical information allow reflecting layers in seismic profiles to be correlated with specific rock units in the stratigraphic sequence. The seismic study now in progress is crucial to confirming the absence of major faults in the region, and to firmly establishing the continuity of the lithology and the thickness of the targeted bedrock units, the Galena and Platteville Groups. The uniform composition and continuity of the dolomite units is obvious from seismic data already acquired. When the final data are compiled and processed, the results will be published. Geophysical data were also acquired on rock lithology, thickness, radioactive constituents, and porosity. Logs show that the Galena and Platteville Groups form a thick, homogenous unit that is low in porosity. Shale and clay are present only as thin partings. Spectral gamma ray logs show that levels of radioactive minerals in the bedrock are very low; they do not exceed 5 parts per million (ppm) for uranium, 6 ppm for thorium, and 6 percent concentration for potassium. Caliper logs indicated little change in the hole diameter of the Galena-Platteville interval, further confirming the generally stable and massive characteristics of the dolomites. Videocamera imaging also showed the units to be generally massive, with some shale partings and a few fractures. Some intervals were vuggy; others were featureless. Geotechnical studies included the acquisition, description, and testing of 4-inch-diameter rock cores recovered from the Maquoketa, Galena, and Platteville Groups. Cores were examined for joints and other discontinuities, then tested to determine basic rock properties, such as specific gravity, unconfined compressive strength, point load indices, and Shore hardness. This information was supplemented by the data from geophysical logs to provide a complete description of the rock characteristics. Analyses indicate that the dolomite of the Galena-Platteville forms an excellent tunneling medium, but is not excessively hard rock (Shore hardness of 72 to 85) that would resist boring. Most fractures are healed (96 percent) and sound (96 percent). The dolomite cores had a Rock Quality Designation of 93.0 to 98.2 percent. Unconfined compressive strength ranged from 4,400 to 14,900 pounds per square inch (psi), and indirect tensile strength and point load indices were also high. A pump test conducted in the upper Ancell Group (below the units where the SSC tunnel would be constructed) gave a transmissivity of 21,000 gallons per day per foot (gpd/ft), hydraulic 3 conductivity of 2.8 x 10" centimeters per second (cm/sec), and a storage coefficient