Fly-ash-based controlled low-strength material (CLSM) used for critical microtunneling applications

Conference · Thu Oct 01 04:00:00 EDT 1998

OSTI ID:651166

Green, B H; Staheli, K; Bennett, D; Walley, D M ^[1]

---

1. Army Engineer Waterways Experiment Station, Vicksburg, MS (United States)

A controlled low-strength material (CLSM) has been successfully used in two microtunneling applications. This CLSM, developed at the U.S. Army Engineer Waterways Experiment Station (WES), is a mixture of ASTM Class C fly ash, ASTM Type I portland cement, bentonite, and water. The CLSM was first used during the microtunneling field trials at WES to stabilize a tunnel excavation while retracting the microtunneling machine through unstable, flooded, running sand. The void left by the retracted tunnel machine was filled with the CLSM to provide continuous support to the excavation and avoid settlement of the ground surface. Based on the success of the WES tests, the CLSM was used on a second microtunneling project in Newark, California. The CLSM was used to stabilize the soil surrounding the sheet-piled shaft that would be used to launch a microtunnel boring machine. The use of this fly-ash-based CLSM greatly improved the stability of the soils and safety of the shaft during the launch. The use of the CLSM also provided cost savings in excess of $100,000 on the Newark project.

• OSTI ID: 651166
• Report Number(s): CONF-970675--; ISBN 0-8031-2477-5
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
42 ENGINEERING
BACKFILLING
BENTONITE
COMPOSITE MATERIALS
COST BENEFIT ANALYSIS
FLY ASH
PORTLAND CEMENT
TUNNELING
WASTE PRODUCT UTILIZATION
WATER