NASCLA Commercial Building Practice Exam 2025 - Free Commercial Building Practice Questions and Study Guide

The term that describes the load per unit area at which a soil will fail in compression is unconfined compressive strength. This measure is critical for understanding the strength characteristics of cohesive soil in the absence of any lateral pressure, which is often encountered in field conditions. Unconfined compressive strength is determined through laboratory tests, typically involving cylindrical soil samples that are compressed until failure occurs.

This value is particularly important in geotechnical engineering, as it helps engineers assess the bearing capacity of soil for foundations and other structures. Understanding unconfined compressive strength allows engineers to predict how much load the soil can support before it yields, enabling safer and more effective design decisions.

Other terms in the context of soil mechanics hold different meanings. Soil shear strength pertains to the maximum resistive force that soil can exert against shear stress, while moisture density refers to the weight of moisture present in the soil, impacting its overall stability but not directly indicating failure under compression. Pore water pressure is the pressure exerted by water within the soil's voids, which also influences soil behavior but does not define the load-bearing capacity in terms of compressive strength.