Prediction of Depth Distribution Curve of Dissolution Rates Based on the Undulating Features of Rock Surfaces

Abstract

In karst regions, the drilling into the rock layer is restricted, if the construction site has a thick overburden and a small upper load. The evaluation of karst development features beneath the site becomes a common technical difficulty in building foundation engineering. Drawing on our previous research into the depth distribution features of dissolution rate, this paper collects 1000 plus data on typical karst regions across China, and selects 65 data for detailed analysis. Specifically, the rock surface dissolution features were analyzed on the top and bottom of the strong dissolution zone, and used to set up the control conditions for the top and bottom predictions of the strong dissolution zone. On this basis, the authors provided a prediction method for the depth distribution curve of dissolution rates. The results show that the elevation of 75% dissolution rate can be regarded as the top elevation of the strong dissolution zone at the site, which controls the prediction error within 0.5 m. If the pores and fissures are not so developed at the karst site, the elevation of 15% dissolution rate can be regarded as the bottom elevation of the strong dissolution zone at the site. According to the top and bottom elevations, the authors derived the predicted curve of the depth distribution function for the dissolution rates at each site. The predicted curve basically overlapped the curve and scatterplot of the dissolution rates measured at the site, a sign of reliable prediction. The proposed prediction method for the depth distribution curve of the dissolution rates at karst construction sites mainly applies to the sites with undeveloped to moderately developed pores and fissures. Further research is needed to verify its effectiveness in sites with strongly developed pores and fissures.

Keywords

• karst
• karst development
• rock surface undulation
• strong dissolution zone