This paper presents the development process of fabricating an analog sedimentary rock in the laboratory. This analog material is characterized by a notably low uniaxial compressive strength (UCS), yet it exhibits brittle behavior. The main objective of this paper is to develop, with a mix of constituents, sample preparation procedures, and engineering treatment within a trial-and-error framework to achieve a material with the desired behavior. The developed analog sedimentary rock is primarily aimed to support the study of brittle failure instabilities encountered during tunnel excavation. Laboratory tests such as unconfined compression, Brazilian splitting, and triaxial compression tests were conducted to characterize the behavior of the analog material. These targeted rock mechanical characteristics of the analog materials encompass four key aspects: (1) showing a very weak UCS of approximately 1.5 MPa, coupled with a postpeak strain softening behavior; (2) exhibiting an uniaxial compressive to indirect tensile strength ratio within the range of 8–10; (3) enhancing Hoek–Brown constant m_i; and (4) achieving selected brittleness indices such as strength brittleness index, brittleness index modified, and burst energy coefficient that are associated with bursting tendency. Several engineering treatments were methodically explored, including uniformly graded fine aggregate usage, lower cement content, curing time reduction, air-entraining admixture usage, saturation and freeze temperature exposure, and thermal exposure. The result is a uniform and isotropic analog rock that can be replicated, similar to mortar mixing. The mixture includes fine-grained F-75 Ottawa sand, type I/II portland cement, and distilled water, with a low cement content of 4 % and a water-to-cement ratio of 1.2. This analog rock provides a controlled, replicable framework for investigating brittle failure instabilities such as spalling and dog-earing in a laboratory-scale tunnel excavation model.