Pile Hole Research Articles

Construction of 8.0-m Diameter Rock-Socketed Piles in a Large-Scale Deep Excavation

This paper presents a case study involving construction of eight rock-socketed piles with diameter of 8.0 m in the primary part and enlarged diameter of 9.5 m at the base. These mega piles were constructed in a 29.8–33.8 m deep excavation pit. They were believed to be the largest rock socketed piles in the world at the construction time. The project was a critical part of building the 606 m tall Shenzhen PingAn Financial Center. Challenges in the construction of the mega piles include strict requirement on controlling the deformation of the surrounding structures, the presence of fissure groundwater in the bedrock, the excavation of pile holes in moderately weathered to slightly weathered rock, the installation of large reinforcement cages in small construction space, and the placement of massive concrete (i.e., with total volume of more than 1800 m3 per pile). Other interesting features include an in-service metro line existing along the north side of these mega piles within distance of only 21 m, and end-bearing of piles on a strong intact granite rock with maximum unconfined compressive strength of 88.2 MPa. The end bearing capacity of piles was computed based on the rock quality designation index. During the construction, in situ tests were performed to monitor and examine the quality of the piles.

Development and Application of In Situ Plate-Loading Test Apparatus for Landslide-Stabilizing Pile Holes

The horizontal foundation coefficient of pile hole walls is a key factor in the design and maintenance of stabilizing piles. An automatic bearing plate-loading test apparatus was developed to measure the horizontal foundation coefficient of a pile hole wall based on an in situ test. The apparatus has an integral structure, providing two switchable loading modes, i.e., a displacement-control mode and loading-control mode, and all functional parts are integrated into a removable unit. The loading frame is controlled by a proportion integration differentiation closed-loop controller, and its rigidity compensation is considered if a transmission column is used for the large span. The process of the field test is described, including the selection of the test location, preparation of the test hole and operation of the test apparatus. The corresponding relationships between the displacement-foundation coefficient (S-K) curves and the deformation and failure stages of the rock mass during the test are analysed. The accuracy of the test results is assessed via comparison with the corresponding rock layer in the current specification.

Study of Application of the Bored Pile Technology in Building Construction

<p>Bored piles involve making pile holes in the site needing pile by mechanical drilling methods and other methods, then placing the pile made of reinforcing cage and pouring concrete inside the holes. Bored piles have smaller vibration and noise compared to sinking pile by hammer method, and are suitable for all kinds of foundations, thus getting the favour of construction enterprises in recent years and is widely used in construction engineering. However, during the process of borehole piling, the bearing capacity of the pile was severely affected by the quality of construction and it is difficult to control the quality of concrete. Hence, bored pile technology is very important. This study will mainly discuss bored pile technology in building construction.</p>

Study of Application of the Bored Pile Technology in Building Construction

<p>Bored piles involve making pile holes in the site needing pile by mechanical drilling methods and other methods, then placing the pile made of reinforcing cage and pouring concrete inside the holes. Bored piles have smaller vibration and noise compared to sinking pile by hammer method, and are suitable for all kinds of foundations, thus getting the favour of construction enterprises in recent years and is widely used in construction engineering. However, during the process of borehole piling, the bearing capacity of the pile was severely affected by the quality of construction and it is difficult to control the quality of concrete. Hence, bored pile technology is very important. This study will mainly discuss bored pile technology in building construction.</p>

Working Performance Analysis and Optimization Design of Rotary Drilling Rig under on Hard Formation Conditions

The rotary drilling rig rapidly popularized in the construction project because of its efficiency, quickness, environmental protection, good hole-forming quality and other advantages. But in drilling hard rock, there are some problems, such as low service life of key position, low construction efficiency and others,. In this paper, these existing problems for power head, drill pipe etc. of working device of rotary drilling rig were analysed. The rotary drilling rig power head removable combined drive key design and rotating seal transition device design which is adapted to drill hard formation put forward the innovation. The rotary drilling rig power head and drill pipe were optimized design and improved. The productive test of rock pile hole drilling which drilling depth is 80m and hole diameter is 2m at fourth tender section on Qingzhi highway, GuiZhou province, shows that the working device optimized and improved well meet the requirements of the pile hole drilling construction under hard formation conditions.

Buckling Analysis of Steel Cylinder in Super Long Bored Piles Construction

This study focuses on buckling analysis of steel cylinder in super long bored piles during construction. Due to special reasons, a steel sleeve is needed to be put into a 92m-long bored pile hole. On the basis of the theoretical estimation and numerical calculation of the steel cylinder, analysis model is established and the highest first pouring height is got. To ensure construction safety, casting speed can be from slow to fast and we can place level or toroidal support at appropriate placement of the steel cylinder. Moreover, test was done and the results show that the wall is in good condition, and the strength and stiffness satisfy the design requirements.

Study on the Effect of Vibration Loads Induced by Bridge Pile Foundation Construction on Adjacent Buried Pipeline

Building up the 3D numerical analysis and computing model, force properties of buried pipelines under vibration loads induced by bridge pile foundation construction were researched, to evaluate and control the influence of construction vibration on adjacent buried pipeline. It was concluded that the most adverse position of impact loads effect on pipeline appeared in the upper right and lower left parts of the pipeline closed to the side away from the pile hole about a quarter of an arc. And the peritubular stress distribution curve with the change of the vibration source location were approximately sinusoidal line, parabola and the cosine line changes. Another, under the same conditions, the vibration velocity of ground above the pipeline was significantly greater than the pipeline itself vibration velocity, so through a reasonable assessing and controlling the vibration velocity of ground above the pipeline, it could be made security decisions for buried pipelines. Finally, according to the horizontal spacing of the buried pipeline and shock vibration source, the pipeline grading protection measures were proposed, with achieving better results in engineering application. Research results could provide some evidence both for the force calculation and design construction of the pipeline project, and support for scientific decision-making of the bridge pile foundation construction. It has an important social and economic efficiency.

Study and Application of PBA Tunneling Technology in Shenyang Metro

The construction procedure of subsurface excavation method is very complex. In order to obtain the regular pattern that the construction process of pile hole may influence the ground surface subsidence, the author use Lizheng software to analysis the construction parameter of excavation, installation and removal of the support, back building etc. Using the finite element analysis method, the author simulate the surface subsidence. Comparing the simulation results with the measured data, the author get the regular patter of surface subsidence and the envelope diagram of Internal force and displacement of the retaining pile.

The Optimization Program of Reverse Circulation Drilling Equipment

Based on the analysis of the problems about the reverse circulation drilling in the practical application, such as the ability of the drilling depth, application in the loose layer, the construction of the pile hole with large diameter, three optimization programs are put forward, and evaluated in combination with the project examples of Wuhan Baishazhou cable-stayed bridge. Finally, some experiences in construction practices are given.

Research on the Factors Affecting the Stabilization of Bored Pile Hole Wall

Numerical analysis on the influencing factors of hole wall stabilization was conducted based on a large bridge approach construction. The geotechnical engineering finite-element analytical software called Plaxis was used for the analysis. The research results indicate that, without considering the influence of the adjacent old pile foundation, the aperture, hole depth, specific gravity of slurry, protective barrel depth, and hole forming time are the key influencing factors that affect the stabilization of bored pile hole wall. On the contrary, when the influence of the adjacent old pile foundation was considered, the protective barrel and the proper depth of the protective barrel may assure the reduction of the interrelationship between the new pile foundation and the adjacent old pile foundation. The research results may be applied to increase drilling efficiency, effectively control the impact of two extremely close adjacent pile foundations, and ensure construction safety.

Research on the Construction Technique of Super-Large Diameter Rock-Socketed Piles in Karst Areas

It is difficult for the large diameter pile to bore the hole and ensure its quality under the complicated geological condition in karst areas. In order to get the feasible construction method, the construction technique of super-large diameter rock-socketed piles in karst areas was explored in this paper on the basis of Hezhang Super Maior Bridge project in Guizhou province. The adaptability of the construction plan at this site was expounded firstly; and then the technologies for dealing with the problems of buried hammer, inclined hole, slurry leakage, which often occur during the process of boring pile hole under complicated geological conditions, were deeply researched. The research results show that it is effective to use the slurry with the relative density of 1.30 to 1.35 to prevent the pebble soil layer from collapsing, to prevent the pile hole from inclining by backfilling rubble in tilted stratum, to treat the slurry leakage problem by backfilling rubble, clay soil and bagged cement; and to handle the hammer stuck through the skills of underwater blasting, salvaging with pothook and light pounding with small hammer. It is proved that the method of light pounding with small hammer is preferable to handle the stuck hammer occured in backfill hole. The study provides the theoretical guidance and reference for similar projects.

Research on the Construction Technique of Super-Large Diameter Rock-Socketed Piles in Karst Areas

It is difficult for the large diameter pile to bore the hole and ensure its quality under the complicated geological condition in karst areas. In order to get the feasible construction method, the construction technique of super-large diameter rock-socketed piles in karst areas was explored in this paper on the basis of Hezhang Super Maior Bridge project in Guizhou province. The adaptability of the construction plan at this site was expounded firstly; and then the technologies for dealing with the problems of buried hammer, inclined hole, slurry leakage, which often occur during the process of boring pile hole under complicated geological conditions, were deeply researched. The research results show that it is effective to use the slurry with the relative density of 1.30 to 1.35 to prevent the pebble soil layer from collapsing, to prevent the pile hole from inclining by backfilling rubble in tilted stratum, to treat the slurry leakage problem by backfilling rubble, clay soil and bagged cement; and to handle the hammer stuck through the skills of underwater blasting, salvaging with pothook and light pounding with small hammer. It is proved that the method of light pounding with small hammer is preferable to handle the stuck hammer occured in backfill hole. The study provides the theoretical guidance and reference for similar projects.

Hybrid Control for Isolation and Energy Dissipation Systems of Flexible Pile

In this paper, a hybrid control system of the energy dissipation and isolation of flexible pile(EDIPF) is proposed, the dynamic analysis model of system is established, and its vibration and control equations are derived. Taking a typical flexible pile base-isolated structure for example, the isolation performance, control effect and main control parameters are studied. The results show that: the isolation and energy dissipation system of flexible pile can effectively reduce the seismic responses of structure, and to apply active control to this system can reduce the possibility of collision between pile and wall of pile hole. At the same time, the vertical loads and the stiffness of superstructure and piles have a significant influence on the control effect of structures.

Exploring the Relationship between the Bottom Rocks of the Pile and the Pile Hole Cleaning

At present, a lot of highway and railway development tend into use the bridge to replace of the road basis. It makes the construction of pile to be the core of the project. The hidden pile makes the construction to be more difficulty, but the technology of the ultrasonic texting improves the quality of the pile. Engineering practices have proved there has some closely relationship between the thickness of the end snaked grains and the pile supported strata stress.

Cast-in-place pile hole driving by means of spiral-shaped device

Cast-in-place pile hole driving by means of spiral-shaped device

Construction of pile holes in permafrost soils with boulders

Construction of pile holes in permafrost soils with boulders

Increasing the bearing capacity of piles sunk in predrilled holes in the ground (in order of consideration)

1. A rubble bed with an optimum depth of 2d reduces the normal pressure exerted by a pile on an undisturbed soil by a factor of not less than 4. 2. The content of soil slurry (solution) in a rubble base should not exceed 0.3 of the volume of crushed stone. Otherwise, an ice interlayer may form between the crushed stone and pile. 3. Use of artificial crushed-stone beds under piles sunk in predrilled holes is particularly effective in high-temperature and salt-bearing permafrost. In these cases, the crushed stone strengthens the soil bed and walls of the pile holes during compaction. 4. Use of piles sunk in predrilled holes on rubble beds has made it possible to lower the foundation cost of each multistory dwelling in Norilsk by not less than 78,000 rubles.