1、GEOTECHNICAL SPECIAL PUBLICATION NO. 274 GEOENVIRONMENTAL ENGINEERINGHONORING DAVID E. DANIEL SPONSORED BY Geo-Institute of the American Society of Civil Engineers EDITED BY Craig H. Benson, Ph.D., P.E. Charles D. Shackelford, Ph.D., P.E. Published by the American Society of Civil Engineers Publishe
2、d by American Society of Civil Engineers 1801 Alexander Bell Drive Reston, Virginia, 20191-4382 www.asce.org/publications | ascelibrary.org Any statements expressed in these materials are those of the individual authors and do not necessarily represent the views of ASCE, which takes no responsibilit
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8、ight 2016 by the American Society of Civil Engineers. All Rights Reserved. ISBN 978-0-7844-8017-5 (PDF) Manufactured in the United States of America. Preface These proceedings are dedicated to David E. Daniel in recognition of his contributions to the field of geoenvironmental engineering. The proce
9、edings are also an expression of gratitude for the friendship, mentoring, and collegiality he has shared with the authors in these proceedings over the last 35 yr. His focus on excellence, dedication to service, and unwavering emphasis on integrity have had a profound influence on each of the author
10、s in this proceedings. Daniel is a founding father of the professional discipline now known as geoenvironmental engineering, which originated in the late 1970s in response to high demand for knowledge regarding environmental processes that affect the fate and transport of contaminants in the subsurf
11、ace. In 2000, Daniel was elected to the National Academy of Engineering, the most prestigious honor recognizing engineering achievement in the United States, for his leadership in developing the field of geoenvironmental engineering and his major contributions to engineering practice regarding waste
12、 containment systems. Most of Daniels professional work in geoenvironmental engineering has focused on engineered barriers for waste containment systems. His seminal contributions underpin our knowledge of the engineering behavior of clay barrier materials and have directly influenced how clay barri
13、ers are designed and deployed in practice. Examples of his contributions include the importance of scale effects when interpreting data regarding the performance of engineered soil barriers, development of laboratory and field methods for measuring the hydraulic conductivity of engineered barrier ma
14、terials, development of modern performance-based compaction criteria for compacted clay barriers, and the role of chemical transport in engineered barrier design, including the potential effects of chemical incompatibility on barrier performance. Daniels seminal contributions on engineering behavior
15、 of geosynthetic clay liners led to their widespread adoption in engineering practice. The papers in this proceedings reflect the impact of Daniels contributions to geoenvironmental engineering. The papers describe case histories of engineered barriers for containment systems as well as fundamental
16、studies on laboratory methods to measure hydraulic conductivity, chemical transport through vertical barriers with enhanced attenuation capacity, and the fundamental behavior of active clays used for engineered barriers. Daniel is a staunch advocate of peer review and excellence in engineering resea
17、rch and practice. Consistent with this philosophy, each of the papers in these proceedings was deemed acceptable for publication only after an affirmative review by two anonymous reviewers, in accordance with the policy of the American Society of Civil *HRHQYLURQPHQWDO(QJLQHHULQJ*63 LLL$6 Beth A. Gr
18、oss, Ph.D., P.E., M.ASCE2; Andrew Brown, Ph.D., P.E., A.ASCE3; and Ranjiv Gupta, Ph.D., P.E., M.ASCE4 1President and CEO, Geosyntec Consultants, 2002 Summit Blvd, NW, Brookhaven, GA 30319. 2Senior Principal, Geosyntec Consultants, 8217 Shoal Creek Boulevard, Austin, TX 78757. 3Senior Staff Engineer,
19、 Geosyntec Consultants, 8217 Shoal Creek Boulevard, Austin, TX 78757. 4Project Engineer, Geosyntec Consultants, 11811 N. Tatum Blvd, Phoenix, AZ 85028. Abstract: This paper summarizes available liquids management data for double-lined mixed low-level radioactive waste (MLLW) landfills at four U.S. D
20、epartment of Energy (DOE) sites. Information is provided on the design of the landfill liner systems, and performance data (i.e., leachate collection system and leakage detection system flow rate and liquid chemical constituent data) are presented and discussed. Data are presented for three distinct
21、 facility periods: (i) the initial period of operation; (ii) the active period of operation; and (iii) the post-closure period. For three of the facilities, the performance data are analyzed to calculate hydraulic containment efficiencies of the liner systems and to draw conclusions as to whether th
22、e liner systems are performing as expected. The results are also compared to previous data and information developed by the two lead authors for a 2002 U.S. Environmental Protection Agency Technical Resource Document (TRD). Based on the data presented, all four facilities are performing very well in
23、 providing containment and collection of leachate. Performance metrics for the facilities are consistent with those presented in the 2002 TRD. The public availability of data for several of the facilities is limited; more intensive liner system monitoring and information dissemination at DOE MLLW fa
24、cilities is recommended. REVIEW OF U.S. EPA TRD FINDINGS In the late 1990s and early 2000s, the two lead authors collaborated with Profs. David Daniel and Robert Koerner in undertaking an evaluation of the field hydraulic containment performance of double-liner systems at operating and closed landfi
25、lls. Results of the evaluation were published in the U.S. Environmental Protection Agency (EPA) Technical Resource Document (TRD) Assessment and Recommendations for Improving the Performance of Waste Containment Systems (Bonaparte et al. 2002). *HRHQYLURQPHQWDO(QJLQHHULQJ*63 $6 (ii) general cell inf
26、ormation (cell area, waste type, waste height, whether construction quality assurance (CQA) was performed, and dates of construction, operation, and closure); (iii) double-liner system and cover system design details (type, thickness, and hydraulic conductivity of each layer); (iv) leachate collecti
27、on system (LCS) flow rate and chemical constituent data; and (v) leakage detection system (LDS) flow rate and chemical constituent data. The data were sorted according to liner system type, waste type, and site geographic location (indicative of site climate). Most of the landfill cells in the study
28、 had either a geomembrane (GM) primary liner (37% of all cells) or a composite primary liner with GM and compacted clay liner (CCL) components (48%). Some of the GM/CCL composite liners also included a geosynthetic clay liner (GCL) component in a GM/GCL/CCL configuration. Fewer cells (15%) had a GM/
29、GCL primary liner. About 48% of the cells had a sand or gravel LDS, and 52% had a geonet (GN) or geocomposite LDS. In evaluating the LCS and LDS flow rate and chemical constituent data, three distinct landfill development stages were considered. During the initial period of operation, there is not s
30、ufficient waste in a cell to significantly impede the rapid flow of rainfall into the LCS. LCS flow rates during this period are typically highest and respond quickly to rainfall events. LDS flows may also be high during this stage due to drainage of precipitation that entered the LDS during constru
31、ction. Over the active period of operation, the cell is progressively filled with waste and possibly daily cover soils, and LCS flow rates decrease and eventually stabilize. During the post-closure period, the cell has been closed with a cover system that further reduces infiltration of precipitatio
32、n into the waste, resulting in further reduction in LCS flow rates and, consequently, LDS flow rates. In the 2002 TRD, a methodology first presented by Gross et al. (1990) was applied to the LCS and LDS flow data to evaluate primary liner leakage rates. The basic approach involves the evaluation of
33、LCS and LDS flow and chemical constituent data to quantify the portion of LDS flow that can be attributed to primary liner leakage as opposed to other sources, such as (i) water (mostly precipitation) that infiltrates the LDS during construction and continues to drain to the LDS sump after the start
34、 of facility operation (“construction water”); (ii) water that infiltrates the LDS during construction, is held in the LDS by capillary tension, and is expelled from the LDS during waste placement as a result of LDS compression under the weight of the waste (“compression water”); (iii) water expelle
35、d into the LDS from any CCL and/or GCL components of a composite primary liner as a result of clay consolidation under the weight of the waste (“consolidation water”); and (iv) groundwater that infiltrates through the secondary liner into the LDS (“infiltration water”). These potential sources of LD
36、S flow are illustrated in Figure 1. *HRHQYLURQPHQWDO(QJLQHHULQJ*63 $6 (iii) environmental management waste management facility (EMWMF) for remediation of the DOE Oak Ridge Reservation in Oak Ridge, TN; and (iv) Idaho CERCLA Disposal Facility (ICDF) at the DOE Idaho National Laboratory in Idaho Falls
37、, ID. All four of these DOE facilities were designed and constructed following detailed quality control/quality assurance (QA/QC) procedures. The Fernald, OH and Weldon Spring, MO sites are located in the NE region of the *HRHQYLURQPHQWDO(QJLQHHULQJ*63 $6 data wand LDS fS and LDSSpring, Msposition o
38、fition debrisg Site Remncludes a mThe WSDCess of nativC began in1998 to JunThe double7. On the sidgranular drare 80-mil double-concells and dS flows frorom the twldon Sprinonstruction uble-Liner SDC includectober 2001average L. No LCS/Lere only avlows have flow rateO: The 24-aapproximat, treated slu
39、edial Actioonolith of dconsists oe low-permearly 1997une 2001. Fin-liner systeme slopes, a ainage layerthick HDPEtained HDPischarge to em the two o cells areng site is abis presenteSystem Ces monthly a(when all LDS flow ratDS flow dailable for tsteadily decs below 5cre (lined arely 1.48 midge, and r
40、eln Project (Debris cemef two contieability clay, and wasteal closure cm configurageocomposiused on th. The LCS E pipes thaexternal sumcells are commonitored out 37 in. d in DOE ross-Sectionaverage comcells had betes for bothata were fothe post-closreased withgpad and ea) WSDC llion yd3of ated waste
41、s OE 2004; nted with a guous cellsbelow the placement onstructiontion for the ite drainage e base. The and LDS of t penetrate ps. As part bined and separately. Additional (2004) and (Base of bined LCSen closed)cells from und for the sure period. time after 0.2 gpad, *HRHQYLURQPHQWDO(QJLQHHULQJ*63 $6
42、 DOE 2015b). As of mid-year 2015, Cells 1 and 2 are full and have partial interim cover, Cell 3 is nearly full, Cells 4 and 5 are active, and Cell 6 is constructed but has not yet receive waste. The double-liner system configuration for the base of the EMWMF is shown in Figure 9. On the side slopes,
43、 a geocomposite drainage layer is used as the LCS in lieu of the granular drainage layer installed on the base. The geomembranes used in the liner system are 60-mil thick HDPE. The liner system is underlain by a 10-ft thick “geologic buffer zone” comprised of compacted soils. The LCS and LDS of each
44、 landfill cell drain by gravity through double-wall HDPE pipes that penetrate the liner system at the low points for each cell. The leachate drains to leachate manholes outside of the lined footprint, is pumped to leachate storage tanks and a loading station, and then is transferred to the Process W
45、ater Treatment Complex by tanker trucks for treatment and subsequent disposal. Mean average annual rainfall in the Oak Ridge area is about 54 in. Additional information on the EMWMF design and construction is presented in Benson et al. (2008) and DOE (2015b). Available operational data for the EMWMF
46、 include annual average LCS flow rates from 2006 (when Cells 1 through 3 were active) through 2014 (when Cells 1 through 5 were active). These LCS data are shown in Figure 10. Annual average LCS flow rates for the EMWMF have ranged from about 6 to 20% of annual precipitation, with a mean of 14% over
47、 the eight-year monitoring period. The annual average LCS flow rate increased as additional cells became operational from 2006 through 2011 (Figure 10), and then decreased from 2012 onwards. The decrease is likely due to the increasing thicknesses of waste in the cells and also to placement of inter
48、im cover over Cells 1 and 2. *HRHQYLURQPHQWDO(QJLQHHULQJ*63 $6 it is poe facility aleakage rateresents cheanium concble-Liner Sa for the ICn Cell 1 beare shown ow rate waerage flowite location months. Tn about 201previous yege of meanh a mean ofGM/GCL cthis paper dindicates thugh 2014 dithat the lassible that iction leakagequates to mical constentrations rSystem CrosDF includecame activein Figure 1s approximais made uand significhese spike2 and 2014ars, presumannual pre31%. omposite pue to the unat liquid fld not exceendfill “has t simply mee rate. Base72 gpad. ituent d
