岩土体单桥静力触探曲线MCP-DD预测方法研究

MCP-DD prediction method of single bridge static cone penetration curve of rock and soil

  • 摘要: 工程中常采用静力触探获得地层信息,但因触探孔位相对稀疏,场地中存在大量未知区域,影响了设计和施工对地层信息的准确判断。提出一种岩土体单桥静力触探曲线的MCP-DD预测方法:①通过邻域半径搜索算法筛选相关数据点;②基于B样条基函数的改良MCP算法计算相关数据的趋势估计函数;③通过空间相关函数对趋势估计函数进行DD加权,得到综合预测模型。运用该方法预测某工程场地的单桥静力触探曲线,结果表明:相比于线性插值法,MCP-DD预测方法有更高的决定系数R2,平均绝对误差MAE减小26.8% ~55.8%,均方根误差RMSE减小25.2% ~54.9%。此外,预测半径R0的最佳取值范围为25.0~37.8 m,平均相关数据点个数越多,平均相对距离越小,模型预测效果越好。

     

    Abstract: Static cone penetration test is often used in engineering practice to obtain relevant geological information. Yet the relatively sparse arrangement of test holes results in a large number of unknown areas in the site, which could affect the accurate judgment of the actual geological information in engineering design and construction. Therefore, this study proposes MCP-DD (minimax concave penalty-distance determined) prediction method for single bridge static cone penetration curve of rock and soil. It contains three main parts: 1) screen neighboring training data through the neighborhood radius search algorithm; 2) compute trend estimation functions of selected data through the modified MCP algorithm based on the B-spline basis function; 3) weight the trend estimation function by the spatial correlation function to obtain an integrated prediction model. This method was used to predict the single bridge static cone penetration curve of a certain engineering site. Results show that compared with the traditional linear interpolation method, the proposed method exhibits a higher coefficient of determination R2. The mean absolute error MAE reduction reduced by 26.8% ~55.8% and the root mean squared error RMSE reduces by 25.2% ~54.9%. The optimal range for predicting the radius R0 is 25.0~37.8 m. Increasing average number of relevant data points leads to smaller average relative distance between the predicted points and the relevant data points, thus bettering the prediction performance of the model.

     

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