Residential Subsurface Exploration and Slope Stability Analysis

Project Overview

SQ Consultants was retained by a residential developer to assess the feasibility and safety of constructing a two story single family residence adjacent to a steep slope. The developer expressed concern that the additional structural loading could compromise slope stability and potentially contribute to failure.

The slope, located east of the proposed building footprint, exhibited gradients ranging from approximately 3.3H:1V in the upper section to as steep as 2H:1V near the base, with an overall height of roughly 70 feet. To evaluate site conditions, SQ Consultants conducted a subsurface exploration program to characterize the underlying soils, followed by a detailed slope stability analysis to establish a safe and appropriate building location.

Scope of Services

Geotechnical Engineering

• Conducted a site reconnaissance and reviewed available topographic information to assess existing surface and terrain conditions.
• Performed a subsurface exploration program, including soil borings and laboratory testing, to classify and characterize underlying soil conditions.
• Utilized field and laboratory data to complete slope stability analyses evaluating the suitability of the site for residential development.
• Developed geotechnical recommendations for the optimal placement of the residence to reduce the potential for slope instability.

Structural Engineering

• Reviewed geotechnical findings to assess implications for foundation design and structural performance.
• Evaluated site constraints and slope stability outcomes to support safe structural sitting of the proposed residence.
• Provided structural considerations related to foundation type, bearing conditions, and potential mitigation measures associated with slope‑related risks.