Research on Stress and Strength of High Strength Reinforced Concrete Drilling Shaft Lining in Thick Top Soils

Yao, Zhishu; Chang, Hua; Rong, Chuanxin

doi:10.1016/s1006-1266(07)60120-5

Cited by 9 publications

(10 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Consequently, it has become normal practice to construct shafts to depths over 500 m [1]. To accommodate such depths, shaft linings have gradually adopted C60 and higher-strength concretes [2]. Numerous provinces throughout China, including Shaanxi, Gansu, Ningxia, and Inner Mongolia, boast rich coal resources characterized by a thick bedrock on the upper surface, water-bearing bedrock, fissure water in aquifers, and poor preliminary grouting conditions.…”

Section: Introductionmentioning

confidence: 99%

Vibration Failure of Young Low‐Temperature Concrete Shaft Linings Caused by Blasting Excavation

Xie

Zeng

et al. 2019

Advances in Civil Engineering

View full text Add to dashboard Cite

The freezing-blasting method constitutes the only available technique for excavating mining shafts within water-bearing bedrock. This study explores the effects of vibration damage to young C65 concrete shaft linings caused by close-range blasting excavation using the finite element method. C65 concrete test specimens were made in the laboratory and then cured at −7°C, and the elastic modulus, compressive strength, and longitudinal wave velocity were tested. The allowable dynamic tensile strength of the concrete for each mold of the shaft lining was obtained according to the observed strain rate of the concrete shaft lining using a regression formula. The finite element simulation results are basically consistent with the in situ measurements, thereby attesting to the validity of the numerical simulation. The blasting-induced vertical peak vibration velocity of the first mold of the concrete shaft lining reached 20∼25 cm/s, which far surpasses the allowable vibration velocity range (i.e., 2∼3 cm/s) in the Safety Regulations for Blasting for newly cast concrete between the initial setting and an age of 3 d. The tensile stress of the first concrete mold calculated by the finite element method is approximately equal to the theoretical tensile stress, both of which are smaller than the dynamic tensile strength of concrete. The cumulative energy sustained by the shaft lining of each mold and the allowable values of the dynamic tensile strength were obtained. The growth rate of the dynamic tensile strength of the subsequent molds was larger than that of the cumulative energy, and thus the safety of the shaft lining gradually improved. The C65 concrete would therefore not experience tensile failure after the shaft lining has sustained multiple rounds of blasting loads. This finding can provide a basis for safety considerations when employing the freezing-blasting method to construct mining shafts in water-bearing bedrock.

show abstract

Section: Introductionmentioning

confidence: 99%

Vibration Failure of Young Low‐Temperature Concrete Shaft Linings Caused by Blasting Excavation

Xie

Zeng

et al. 2019

Advances in Civil Engineering

View full text Add to dashboard Cite

show abstract

“…Concrete structures in underground environments not only suffer from attack by chemical substances but also from high stresses induced by underground water in the overlaying soil and surrounding rock that can lead to structural damage (Ahmad and Azhar, 2004;Yao et al, 2007). This stress-induced damage can accelerate sulphate diffusion in concrete leading to concrete damage.…”

Section: Introductionmentioning

confidence: 99%

Sulphate attack resistance of high-performance concrete under compressive loading

Zhao

Cui

et al. 2013

J. Zhejiang Univ. Sci. A

View full text Add to dashboard Cite

Abstract:In this paper, an experimental study on the sulphate attack resistance of high-performance concrete (HPC) with two different water-to-binder ratios (w/b) under compressive loading is presented. The sulphate concentration, compressive strength, and the mass change in the HPC specimens were determined for immersion in a Na 2 SO 4 solution over different durations under external compressive loading by self-regulating loading equipment. The effects of the compressive stress, the w/b ratio, and the Na 2 SO 4 solution concentration on the HPC sulphate attack resistance under compressive loading were analysed. The results showed that the HPC sulphate attack resistance under compressive loading was closely related to the stress level, the w/b ratio, and the Na 2 SO 4 solution concentration. Applying a 0.3 stress ratio for the compressive loading or reducing the w/b ratio clearly improved the HPC sulphate attack resistance, whereas applying a 0.6 stress ratio for the compressive loading or exposing the HPC to a more concentrated Na 2 SO 4 solution accelerated the sulphate attack and HPC deterioration.

show abstract

“…Assuming that the external load is not too large, it is often more practical to analyse the mechanical properties of shaft lining concrete using the Mohr-Coulomb criterion, but it has been found that the mechanical properties of concrete under multiaxial stress should be considered under large external loads [15]. Indeed, the vertical shaft lining of a coal mine shaft constructed using the freezing method in deep alluvium generally adopts a double-layer shaft lining structure type in which the concrete of the inner shaft lining of the freezing well is generally in a bi-or tridirectional stress state [16][17][18]. Because the three-parameter strength criterion [19][20][21][22] considers the influence of multiaxial stress, it is better equipped to reflect the mechanical properties of an HSHPRCSL under multiaxial stress.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Properties of High‐Strength High‐Performance Reinforced Concrete Shaft Lining Structures in Deep Freezing Wells

Peng

Rong

Cheng

et al. 2019

Advances in Civil Engineering

View full text Add to dashboard Cite

As coal resources must be mined from ever deeper seams, high-strength, high-performance concrete shaft linings are required to resist the load of the soil surrounding the deep freezing well. In order to determine the optimal concrete mix for the unique conditions experienced by such high-strength high-performance reinforced concrete shaft lining (HSHPRCSL) structures in deep freezing wells, an experimental evaluation of scaled HSHPRCSL models was conducted using hydraulic pressure load tests. It was observed that as the specimens ruptured, plastic bending of the circumferential reinforcement occurred along the failure surface, generated by compression-shear failure. These tests determined that HSHPRCSL capacity was most affected by the ultimate concrete uniaxial compressive strength and the thickness-diameter ratio and least affected by the reinforcement ratio. The experimental results were then used to derive fitting equations, which were compared with the results of theoretical expressions derived using the three-parameter strength criterion for the ultimate bearing capacity, stress, radius, and load in the elastic and plastic zones. The proposed theoretical equations yielded results within 8% of the experimentally fitted results. Finally, the finite element analysis method is used to verify the abovementioned results, and all errors are less than 12%, demonstrating reliability for use as a theoretical design basis for deep HSHPRCSL structures.

show abstract

Research on Stress and Strength of High Strength Reinforced Concrete Drilling Shaft Lining in Thick Top Soils

Cited by 9 publications

References 0 publications

Vibration Failure of Young Low‐Temperature Concrete Shaft Linings Caused by Blasting Excavation

Vibration Failure of Young Low‐Temperature Concrete Shaft Linings Caused by Blasting Excavation

Sulphate attack resistance of high-performance concrete under compressive loading

Mechanical Properties of High‐Strength High‐Performance Reinforced Concrete Shaft Lining Structures in Deep Freezing Wells

Contact Info

Product

Resources

About