Twenty years ago, most buildings in the United States were supported by either shallow spread footings or deep foundations. Since then, "intermediate" ground improvement options have increased in use, providing building owners, contractors, and engineers with a host of options each with its own unique design and construction characteristics. Loose sands are now often densified, and soft cohesive soils are reinforced with displacement or replacement aggregate piers prior to shallow foundation construction. For heavier loads and softer soils, the subsurface materials are often now reinforced with "rigid inclusions", typically consisting of cementitious columnar elements installed by either driven-displacement or drilling methods. Organic soils, such as those typically found in New England, the Upper Midwest, and the Pacific Northwest almost always require "improvement" prior to shallow foundation construction because of their inherent compressibility under even small loads. In certain conditions, the organic materials can be reinforced by non-cemented aggregate piers, provided care is used in the appropriate selection of pier stresses to avoid the pier "bulging" and long-term settlement performance issues. In other conditions, such as when the thickness of the organic soils is large, when the loads are heavy, or when the consequences of settlement are severe, more robust solutions, such as those provided by rigid inclusions are necessary. This paper provides the results of multiple case histories in which organic soils have been reinforced by both confined aggregate and cemented ground improvement elements.
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机译：二十年前，美国的大多数建筑都是由浅层蔓延的基础或深层基础的支持。从那时起，“中间”地面改进选项在使用中增加，提供了建筑物所有者，承包商和工程师，其中一系列选项，每个选项都具有自己独特的设计和施工特性。宽松的沙子经常致密化，在浅基础建设之前，用位移或更换聚集码头加固软粘性土壤。对于较重的载荷和更柔软的土壤，地下材料现在通常用“刚性夹杂物”加强，通常由由驱动 - 位移或钻井方法安装的水泥柱状元件组成。有机土壤，例如通常在新英格兰，上部中西部和太平洋西北部发现的有机土壤几乎总是在浅层基础施工之前总是需要“改进”，因为它们在甚至小负荷下的固有压缩性。 In certain conditions, the organic materials can be reinforced by non-cemented aggregate piers, provided care is used in the appropriate selection of pier stresses to avoid the pier "bulging" and long-term settlement performance issues.在其他条件下，例如当有机土壤的厚度很大时，当负载很重时，或者当沉降的后果严重时，必要的稳健溶液，例如由刚性夹杂物提供的那些。本文提供了多种案例历史的结果，其中有机土壤通过狭窄的聚集体和胶结地改善元素加固。
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