某学校建设场地膨胀土形成机制及膨胀土滑坡特征研究

以某学校场地冰碛土滑坡为依托，基于岩石矿物的化学风化原理，在已有小流域地质环境的调查和场地土工试验的基础上，分析了古冰川冰碛物形成膨胀土的条件和过程、玄武岩区冰碛物膨胀土的形成机制、滑坡异常发育的原因，总结了该类膨胀土的滑坡特征。研究表明:冰碛物膨胀土的形成主要是冰碛物在冰川消融之后，气候转暧，生物恢复，使化学风化作用增强，母岩玄武岩中的辉石矿物经化学风化作用转化为亲水性最强矿物蒙脱石，且由于膨胀土遇水变软，极易形成浅层小型滑坡。

Study on the Formation Mechanism of Expansive Soil and the Characteristics of Expansive Soil Landslide in a School Construction Site

Relying on a moraine soil landslide of a school site, based on the chemical weathering principle of rocks and minerals and the investigation of the geological environment of the existing small watershed and the site geotechnical tests, the conditions and process of ancient glacial moraine forming expansive soil, the formation mechanism of expansive soil of glacial moraine in basalt area and the reason of abnormal development of landslide were analyzed and the landslide characteristics of such expansive soil were summarized. The results show that the formation of glacial moraine expansive soil is mainly due to the climate change and biological recovery of the moraine after the glacier melts, which enhances chemical weathering, and the pyroxene minerals in the parent rock basalt are transformed into mineral montmorillonite with the strongest hydrophilicity by chemical weathering and because the expansive soil becomes soft in contact with water, it is easy to form small shallow landslides.