Teller Dam (Colorado, US) - Rehabilitation

The Teller Dam at the Turkey Creek River is located within the U.S. Army post Fort Carson south of Colorado Springs in Colorado. The remediation works are coordinated by the U.S. Army Corps of Engineers (USACE). The prime contractor, Komada LLC, commissioned BAUER Foundation Corp. with the execution of the specialist foundation engineering works. Cut-off wall works included the execution of approximately 12,800 SF (1,189 m²) secant pile wall and 19,000 SF (1,175 m²) of grout curtain treatment at the left abutment of the Fort Carson, Teller Dam.


The intent of the cut-off wall is to intercept potential seepage pathways that could contribute to internal erosion of dam material along the dam and abutment contact. The cut-off wall con- sists of two sections, a secant pile wall through the left end of the dam and  abutment and at the abutment contact, and a grout curtain to further extend the interception of seepage pathways at the left abutment.


The secant pile wall and grout curtain total length in plan view is approximately 350 linear feet (106 m) reaching a maximum depth of 120 ft (36.5 m).


The piles for the secant pile wall have a diameter of 59 inch (1,500 mm) and were constructed with a BAUER BG 39 in combination with a casing oscillator for the temporary segmental casing installation. The pile execution had to follow tight verticality requirements and a minimum pile overlap and minimum continuous  cut-off wall thickness had to be guaranteed throughout the entire pile length, despite the challenge of a very steeply angled soilrock interface. According to the specification, three different methods for verticality measurements (DIS, RIS, PRAD) had to be executed to confirm the required cut-off wall parameters. In addition, verification holes were cored between two adjacent piles and CCTV and OPTV surveyed.


The actual grout curtain installation included drilling of the embankment soil and bedrock and specific  core  drilling  in the bedrock (shale  and  sandstone)  in combination with packer grouting under consideration of a Klemm 806 drilling rig, drilling rig for  sonic  method, automated grout plants and a grout buggy. Grouting works included  realtime computer monitored single and double packer grouting considering the upstage grouting method but also the downstage grouting method in specific cases. Lugeon testing and OPTV surveys were executed to identify potential rock fissures.

The encountered bedrock during the cut-off wall installation is a mixture of Glencarin shale and Dakota sandstone, with rock strength (UCS) exceeding 14,500 psi (100 MPa).


Client: United States Army Corps of Engineers 
Employer:    Komada LLC
Execution: BAUER Foundation Corp.

Scope of works: 


  • 12,800 SF (1,189 m²) of secant pile wall
  • 9,000 SF (1,175 m²) of grout curtain using single and double packer injections

Construction period:  

August 2019 – October 2020