Pai Jiang

In response to the issue of the size effect of helical anchors in deep-sea areas on their uplift bearing capacity, this study was proposed based on the ratio of the anchor shaft diameter to the anchor helix diameter and the ratio of the pitch to the anchor helix diameter. Eight sets of small-scale anchors were designed for laboratory model tests to study the impact of different anchor shaft diameters to anchor helix diameter ratios and the ratio of the pitch to the anchor helix diameter on uplift bearing capacity. The results indicate that smaller ratios of the anchor shaft diameter to the anchor helix diameter and the pitch to the anchor helix diameter can improve the uplift bearing capacity of helical anchors. In addition, this study found that the uplift bearing capacity of helical anchors decreased with the increase in the ratio of the anchor diameter to the anchor helix diameter and the ratio of the pitch to the anchor helix diameter. Based on this, a prediction equation for the uplift bearing capacity of helical anchors was proposed.

Adding fibers into cement to form fiber-reinforced soil cement material can effectively enhance its physical and mechanical properties. In order to investigate the effect of fiber type and dosage on the strength of fiber-reinforced soil cement, polypropylene fibers (PPFs), polyvinyl alcohol fibers (PVAFs), and glass fibers (GFs) were blended according to the mass fraction of the mixture of cement and dry soil (0.5%, 1%, 1.5%, and 2%). Unconfined compressive strength tests, split tensile strength tests, scanning electron microscopy (SEM) tests, and mercury intrusion porosimetry (MIP) pore structure analysis tests were conducted. The results indicated that the unconfined compressive strength of the three types of fiber-reinforced soil cement peaked at a fiber dosage of 0.5%, registering 26.72 MPa, 27.49 MPa, and 27.67 MPa, respectively. The split tensile strength of all three fiber-reinforced soil cement variants reached their maximum at a 1.5% fiber dosage, recording 2.29 MPa, 2.34 MPa, and 2.27 MPa, respectively. The predominant pore sizes in all three fiber-reinforced soil cement specimens ranged from 10 nm to 100 nm. Furthermore, analysis from the perspective of energy evolution revealed that a moderate fiber dosage can minimize energy loss. This paper demonstrates that the unconfined compressive strength test, split tensile strength test, scanning electron microscopy (SEM), and mercury intrusion porosimetry (MIP) pore structure analysis offer theoretical underpinnings for the utilization of fiber-reinforced soil cement in helical pile core stiffening and broader engineering applications.