Jet-Expanded Conical Frustum Pressure-Grouted Pile Technology

01. Technology Overview

The Jet-Expanded Conical Frustum Pressure-Grouted Pile is constructed using the jet-expansion, squeezing-vibration, and pressure-grouting method to form a reinforced concrete or plain concrete cast-in-place pile composed of a pile shaft, ribs, and expanded-diameter bodies.

The jet-expansion, squeezing-vibration, and pressure-grouting method involves hole formation by a multifunctional spiral drilling rig, high-pressure jetting of cement slurry, pressure-grouting, and squeezing-vibration of super-fluid concrete to form, within the pile shaft length, expanded-diameter bodies and pile shaft ribs composed of a concrete-cement-soil composite, which combine with the concrete pile shaft to form the Jet-Expanded Conical Frustum Pressure-Grouted Pile.

02. Pile Structure and Load-Bearing Mechanism

03. Prominent Technical Features

This is a high-efficiency pile that adopts the jet-expansion, squeezing-vibration, and pressure-grouting method to improve the geometric configuration and mechanical properties of the pile-soil interface, enhance stress diffusion in the soil, and maximize the supporting effect of the geotechnical medium on the pile body. The technology has reached the internationally leading level.

04. Construction Process

05. Technical Advantages

The Jet-Expanded Conical Frustum Pressure-Grouted Pile is constructed using the "jet expansion, squeezing vibration, and pressure grouting" process. Directional jetting of cement slurry along the pile side improves the mechanical properties of the pile-soil interface, eliminates the mud cake on the pile side, increases pile-side friction resistance, and forms pile-side ribs, effectively enhancing stress diffusion in the surrounding soil. The high-pressure rotary jet-expanded body compacts and reinforces the pile-end soil through cement slurry permeation, eliminates sediment, increases pile-end resistance, and forms a pile-end expanded-diameter body that enlarges the load-bearing area at the pile end. This reduces pile foundation settlement deformation and improves the compressive, uplift, and lateral load-bearing capacities of a single pile. Static load tests on single-pile compression show that when reaching twice the characteristic value of single-pile bearing capacity, the single-pile settlement deformation is generally the compression deformation of the pile shaft itself.

The pile construction quality is stable and reliable, and the construction process is simple. A single machine performs hole formation, wall protection, rotary jet-expanded body formation, directional jetting of ribs, squeezing-vibration pressure-grouting of concrete, and installation of the reinforcement cage in a tightly coordinated sequence, with no diameter reduction or hole collapse. Construction speed is fast, with approximately 15 piles completed per machine per day.

The construction process requires no mud, is green and environmentally friendly, low-carbon and energy-saving, and aligns with China's green industry development direction.

The pile is suitable for sand, silt, cohesive soil, gravelly soil, soft rock, and other strata, offering a wide application range and strong adaptability; it can be used as a foundation pile for pile foundations and as a reinforcement body for composite foundations.
06. Technical Standards and Patents

07. Engineering Applications

The Jet-Expanded Conical Frustum Pressure-Grouted Pile has been widely applied in engineering construction, such as the Hefei Xinqiao International Airport T2 Terminal project, the Jiqu Elevated Expressway, and the University of Science and Technology of China Faculty Apartment project, achieving remarkable social and economic benefits.

Key Project of Anhui Province

— Hefei Xinqiao International Airport T2 Terminal Project

Key Project of Anhui Province

— University of Science and Technology of China Faculty Apartment Project

Key Project of Shanxi Province

— Cathay (Taiyuan) Biotech Construction Project

Key Project of Shandong Province

— Jiqu Expressway Project

Key Project of Shandong Province

— Qufu Normal University Qufu Campus Expansion Project

Key Project of Shandong Province

— Shandong Taibai Lake District Shantytown Renovation Project

Key Project of Yunnan Province

— Kunming Tuodong Dacheng Business District Relocation and Resettlement Project