Lemon Lane Final Report
June, 2001
1.0 Introduction | 2.0 Site Description and History | 3.0 Remediation Planning | 4.0 Changes to Original Work Plan | 5.0 Sampling Activities | 6.0 Preparation of Iterim Cap Surface | 7.0 Intallation of the Geosynthetic Clay Barrier | 8.0 Placement of Geomembrane and Geonet | 9.0 Placement of Vegetative Support Zone | 10.0 Site Surface Water Controls | 11.0 Site Restoration | 12.0 Data Validation | Photos
7.0 INSTALLATION OF THE GEOSYNTHETIC CLAY BARRIER
7.1 Inspection and Quality Control of GCL
A two component barrier layer was placed over the cushion soil and waste. The
function of the barrier layer is to prevent infiltration of surface water into the
underlying waste. The lower component of this dual system is the geosynthetic clay
liner (GCL). The GCL material is technically superior to a 24 inch compacted clay
layer with regard to permeability, frost damage and constructibility.
The GCL material came in rolls that were 150 ft. long and 15 ft. wide. A certificate
that identified the origin, brand name and number and certification of quality control
accompanied each roll of GCL. Each roll was identified with a label that contained
the roll number, lot number and date of manufacture. The manufacturer quality
control tests included:
- GCL Dry Thickness
- Bentonite Content
- Hydraulic Conductivity
- Minimum Interface Friction
- Hydrated Internal Shear Strength
As mentioned in Section 6.3 the subgrade for the GCL was compacted, tested and
inspected prior to placement.
7.2 GCL Installation
Installation of the GCL started at the northeast edge of the site on October 25, 2000.
In general, the GCL was rolled out and placed parallel to the landfill slopes. The
GCL extended at least three feet beyond the LOC. Horizontal seams were only
permitted on slopes that were less than 10%. Seams consisted of at least 6 inches
overlap on the sides and at least 12 inches on the ends. Once placed, the seams
were inspected for wrinkles or creases and the surface inspected by Envirocn and
Colder representatives. The GCL surface was inspected in preparation for
placement of the 40 mil geomembrane. All GCL placed on any given day was
covered with geomembrane to protect the GCL from becoming hydrated due to rain
or surface water. At no time was any of the GCL hydrated due to standing water or
rain.
|
