Laserfiche WebLink
Hana Japan Restaurant Project <br />Initial Study/Mitigated Negative Declaration <br />44 <br />May 2025 <br />notes that structural areas could be sensitive to settlement of compacted soil. Such areas <br />include, but are not limited to, building pads, sidewalks, pavement areas, and retaining <br />walls. Therefore, without implementation of the recommendations contained within the <br />Geotechnical Report, the proposed project could be subject to subsidence/settlement. <br /> <br />Expansive Soils <br />When subsurface earth materials move, the movement can cause the gradual settling or <br />sudden sinking of ground. The phenomenon of settling or sinking ground is referred to as <br />subsidence, or settlement. Expansive soils are soils which undergo significant volume <br />change with changes in moisture content. Specifically, such soils shrink and harden when <br />dried and expand and soften when wetted, potentially resulting in damage to building <br />foundations. <br /> <br />As part of the Geotechnical Report, ENGEO conducted a field exploration and obtained <br />soil samples from the project site on April 15, 2008. The samples were analyzed to <br />determine the engineering properties of the soils, including compression, plasticity index, <br />direct shear, and soil corrosion potential. Based on the results of the analysis, expansive <br />soils are located on-site. Specifically, shallow depths of expansive clay were found in <br />Borings 1-B2 and 1-B3, and deeper areas of expansive clay were identified in Borings 1- <br />B1 and 1-B4 (see Figure 8). Although such soils are anticipated to be removed from the <br />project site during site preparation and grading associated with the proposed project, any <br />remaining soils located beneath the proposed building could subject the restaurant to <br />adverse effects. <br /> <br />Based on the above, the proposed project could be subject to substantial adverse effects, <br />including the risk of loss, injury, or death involving expansive soils. <br /> <br />Conclusion <br />Based on the above, without proper implementation of the recommendations included in <br />the updated Geotechnical Report prepared for the proposed project, the proposed project <br />could result in potential hazards or risks related to lateral spreading, subsidence, and/or <br />expansive soils, and a potentially significant impact could occur. <br /> <br />Mitigation Measure(s) <br />Implementation of the following mitigation measures would reduce the above potential <br />impact to a less-than-significant level. <br /> <br />VII-1. Prior to approval of Improvement Plans, the plans shall include all relevant <br />2022 CBSC standards, as well as all recommendations included within the <br />updated Geotechnical Report (2025) and the Fault Exploration report (2008) <br />prepared by ENGEO Incorporated to ensure that the recommended standards <br />are incorporated into project design and construction. All project improvement <br />plans shall be reviewed by a licensed engineer and approved by the City of <br />Pleasanton Community Development Department and the City Engineer. <br /> <br />VII-2. Prior to commencement of building construction and during cut and fill activities <br />associated with the proposed project, any potentially expansive clay <br />encountered within building pads shall be removed to a depth of at least three <br />feet below pad grade, as determined by a licensed geotechnical engineer. In <br />addition, potentially expansive clay shall not be placed within the upper three