Observations/Finding

As requested, the site was visited by our AS Engineering and Consulting (ASEC) representative for the purpose of providing quality control inspection and testing services.  Visual observation techniques were employed to verify compliance with project drawing/specifications, applicable codes, and materials submittals. The following observations were observed on site this day.

The following report outlines the installation process of sanitation sewer between 7A-12 and the Lot #1 lateral, along with testing conducted on the retaining wall footing adjacent to Lots #24 and 25.

Sanitation Sewer Installation:

• A layer of 12 inches of #57 stone was placed between 7A-12 and the Lot #1 lateral.
• Initial probing of the first soil lift with a 3/8 inch probe was at 1 inch deflection.
• Subsequent lifts were placed, compacted using a trench packer, and tested with a Troxler 3430 (serial # 30942). (see attached test report)

Retaining Wall Footing Testing:

• Testing was conducted on the retaining wall footing adjacent to Lots #24 and 25 using a Dynamic Cone Penetrometer (DCP).
• The footing, 4 feet wide, was probed and found to contain a mixture of soil and rock fragments, with some water intrusion.  (see photos)
• Two test points were selected:
  • Test 1: 5 feet from the North end of footing:
    • Foot 1: Brown Sandy Silt, DCP reading = 16 blows
    • Foot 2: Brown Sandy Silt with Clay, DCP reading = 11 blows
    • 3-foot Auger Refusal (AR)
  • Test 2: 5 feet west of corner:
    • Foot 1: Brown Sandy Silt, DCP reading = 10 blows
    • Foot 2: Brown Sandy Silt with Clay, DCP reading = 9 blows
    • Foot 3: Auger Refusal (AR)
• Several Auger Refusals (AR) were encountered throughout the footing due to the presence of rock fragments.

Samples: A soil sample, designated by the wall crew foreman, was obtained and taken to the lab for testing to perform a moisture-density relationship for future wall back filling.

Recommendations: Due to the soft soils and water intrusion observed, the ASEC Engineer recommended the following actions:

• Removal of an additional 6 inches of soil from the affected area.
• Placement of #57 stone at a level higher than the observed water intrusion, covering an area of approximately 23 feet x 8 feet.

Attachments:

• Testing Report
• Photos (Sanitation sewer installation, Retaining wall footing testing)

Retaining wall footing on lot #25

Sanitation sewer 7A-12 to Lot 1

Sewer

Lot #1 sanitation sewer lateral

retaining wall footing with water intrusion

retaining wall footing with water intrusion