Combining correlation analysis and establishing empirical relationship is a common method for geotechnical parameters prediction in geotechnical engineering. This method can quickly and efficiently predict geotechnical parameters through some easily obtained geotechnical testing data. Taking the geotechnical parameters of the cohesive soil in the lower part of Gehu Formation in Changzhou area as the research object, 102 groups of geotechnical testing data were selected, and the geotechnical parameters prediction model based on the multiple regression model and information entropy was established. Firstly, the cohesion and internal friction angle of quick direct shear test were determined as the prediction objects, and the influencing factors were density, water content, void ratio and liquidity index. Then, through the regression analysis of SPSS software, the optimal single factor fitting model was determined, and calculated the weight of the influencing factors by using the method of information entropy to obtain the improved multiple regression forecast model. Finally, the standard error analysis method was used to analyze the prediction results. The results show that: The density has a positive correlation with the cohesion and the internal friction angle, respectively, and the other factors have a negative correlation with the cohesion and the internal friction angle, respectively. The mean error of the predicted value of cohesion is -1.34 kPa, and the normalized root mean squared error is 12.00%. The mean error of the predicted value of internal friction angle is -0.05°, and the normalized root mean squared error is 18.30%. The study shows that the prediction model has high reliability and can effectively predict the cohesion and internal friction angle of cohesive soil in the lower part of Gehu Formation in this area. This method provides a way of thinking for the prediction of geotechnical parameters.

Obtaining undisturbed high-quality samples is a challenge in geotechnical investigation, and soil samples will be disturbed to some extent in the process of drilling and sampling. In order to study the influence of sampling technology on the quality of soil samples when sampling in saturated soft clay strata, this paper takes a typical silt in Wenzhou, Zhejiang Province, as the research object. Firstly, the stratigraphic distribution of the site was understood by cone penetration test (CPT). Then, comparative tests on the quality of soil samples were conducted by using cryptomorphic shaft-valve type soil sampler, conventional thick wall sampler and open end thin wall sampler, respectively. Through a comparative analysis and research on the appearance morphology, unconfined compressive strength and sensitivity index, disturbance index of soil samples, a quantitative analysis and evaluation of the influence of different sampling technology on the quality of soil sample of the saturated soft clay was finally obtained. The results of the study showed that using the cryptomorphic shaft-valve type soil sampler has the least disturbance and the highest quality on sampling, the open end thin wall sampler is the second, and the conventional thick wall sampler has the highest disturbance and the worst quality. The cryptomorphic shaft-valve type soil sampler has 20.2% higher unconfined compressive strength average value than the conventional thick wall sampler and 10.3% higher than the open end thin wall sampler. Using the rate of change of pore ratio under self-weight stress as a quantitative indicator of the magnitude of soil sample disturbance, the conventional thick wall sampler with the worst soil quality has 11.0% greater than the average value of the best cryptomorphic shaft-valve type soil sampler. The sampling technology of the cryptomorphic shaft-valve type soil sampler takes soil samples of relatively highest quality in saturated soft clay, and the geotechnical parameters obtained after the test are relatively close to the physical and mechanical characteristics of the real stratum.