研究目的：目前利用扁铲侧胀试验确定土层静止侧压力系数方法主要包括基于Mmdlm解与弹性理论 推导的理论公式法和基于试验数据建立的经验公式法。通过本次研究，拟确定上述两种方法中哪一种方法计 算的土层静止侧压力系数更加准确，以利于在今后工程勘察中应用。
研究结论:（1)基于Mmdlm解和弹性理论推导的理论公式是线性的，其结果随角点应力与中心点应力的 比值不同而不同，不易确定；（2)基于试验数据建立的经验关系式是非线性的，符合土体是非弹性体的特性，而且不同地区、不同成因的土层存在差异性，因此基于试验数据建立的经验关系式更适合工程实际；（3)本研 究成果可供铁路、地铁、公路等工程勘察中获取土层静止土压力系数借鉴参考。

Research purposes ： At present，there are two main methods of determining the static lateral pressure coefficient from the flat dilatometer tests which are the theoretical formula method based on the Mindlin solution and elasticity theory and the experience formula method based on the test data of the fat dilatometer tests. Through this research, which of the two methods is more accurate for calculating the static lateral pressure coefficient of the soil layer is determined，and the method can be applied to the engineering exploration in the future.
Research conclusions ：( 1) The theoretical formula method based on the Mindlin solution and elasticity theory is linear，and the result is difficult to determine because it changes with the change of the ratio of the comer point stress and the center point stress. (2) The experience formula method based on the test data of the flat dilatometer tests is nonlinear， which is in line with the characteristics that soil is non - elastomeric，and the soil layers from the different regions and different genesis. So the experience formula method based on the test data of the flat dilatometer tests is more suitable for engineering practice. (3) This research result can provide reference for determining static earth pressure coefficient in the railway，subway，highway and other engineering survey.