It is of significance for pile foundation design and construction to predict the penetration depth accurately of the displacement pile under a fixed pressure. A new type cone penetrometer and corresponding exploration methods are developed through increasing weight of the device, enhancing the strength of probing rod and probe, and embedding a new function on measuring the total penetration resistance. Not only applied appropriately to various strata except for pebble bed, functions such as the total penetration resistance determination, soil layer classification and soil compression modulus and dynamic-static friction ratio calculation are also provided. Data of total penetration resistance, static point resistance and side friction are measured with the new type cone penetrometer, a new coefficient of dynamic-static friction ratio is introduced and employed to calculate the dynamic side friction, a new estimation method, with which the influence of dynamic side friction is take into account, on penetration depth evaluation of the displacement pile is established and proposed subsequently. Validity of the new method is verified by means of case study of pile engineering and the results indicate, for its high accuracy, the method proposed is of practice and theoretical significance, as well as valuable for popularization.

In order to eliminate the out of round defect of grinding ball, an improvement measure is proposed. Firstly, the wear behavior and mechanism of the ball in different service conditions are obtained. Then, the root cause of grinding ball out of roundness is discussed. Finally, the corresponding improvement measures are put forward from the aspects of grinding ball material and heat treatment, so as to improve the microstructure and properties of grinding ball.

On the basis of analyzing the occurring mechanism of pile skin friction, pile-soil relative displacement difference function is introduced, and the differential equation which depicts the relationship between pile skin friction and depth is derived, then the calculating model of pile skin friction with depth is established under considering the displacement-interaction process. Field monitoring data are employed to verify the rationality and validity of the model proposed. Through the established model, influences, exerted by pile-soil relative displacement difference, on the pile skin friction distribution are discussed and divided into three stages: I. stage of linear increase; II. stage of nonlinear increase; III. stage of convergence. Filed testing data comparing and theoretical analysis results indicate that the method proposed can describe the transferring process as well as the distribution law of pile skin friction under taking the pile-soil interaction into account, the parameters related and needed can be easily obtained, and the model suggested in this paper is of value in pile theory and engineering.

According to the limitation on applying the research achievement on regional rainstorm-induced road hazard into practice, formation mechanism and development patterns are analyzed and investigated deeply, then two stages on forming the rainstorm-induced road hazard are verified: ① The hydrodynamic action stage, including the rainstorm splash-wash erosion process and infiltration-seepage process; ② The hydrostatic action stage, including rainwater immersion-softening process. They are combined to establish a series interaction processes termed "splash-wash-infiltration-seepage-immersion-softening" to define the formation mechanism mode for the rainstorm-induced road hazard. full cut,full fill,cut and fillare considered to be the three typical failure patterns for the rainstorm-induced road hazard and all types are boiled down to "cumulative deformation failure → developing and catastrophe failure → hysteretic deformation failure" three failure process, in order to reflecting the occurring and evolving law for the rainstorm-induced road hazard, comprehensive and systematic analysis are implemented into every single failure mode and process. The study achievements indicate a new clue for approaching the formation mechanism and developing mode of rainstorm-induced road hazard, and are of value to disaster prevention and reduction in road engineering.