Reinforcement-Steel Fiber Concrete Shield Segment Normal Section Bearing Capacity and Reinforcement Determination Method

A technology of steel fiber concrete and fiber concrete, which is applied in the direction of testing material strength by applying stable bending force and testing material strength by applying stable tension/compression, which can solve the problems of low accuracy, neglect of tensile properties, and deviations And other issues

Active Publication Date: 2020-11-13
中铁科学研究院有限公司 +1
View PDF10 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the calculation method used in the code takes into account the strengthening effect of steel fiber on the bearing capacity of concrete, there are still the following problems: (1) The tensile strength value of steel fiber reinforced concrete in the code is mainly based on empirical parameters, and the constitutive model is consistent with the actual deviation, the calculation results are conservative and the accuracy is not high; (2) As a member of the ordinary reinforced concrete structure judged to be a large bias, after considering the tensile reinforcement of the steel fiber reinforced concrete, the tensile reinforcement cannot yield when the compression zone is damaged , become a de facto small eccentric component; the regulation considers the limited improvement of the bearing capacity of small eccentric compression components, so it is still calculated according to the current ordinary reinforced concrete structure regulations, ignoring the impact of the improvement of the tensile performance of the steel fiber reinforced concrete after cracking on the eccentric (3) The regulations do not set a limit value requirement for the height of the compression zone to ensure that the compression reinforcement reaches the compressive strength when the component fails
[0004] To sum up, there is currently a lack of an effective method for measuring the bearing capacity of the steel fiber reinforced concrete shield segments.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Reinforcement-Steel Fiber Concrete Shield Segment Normal Section Bearing Capacity and Reinforcement Determination Method
  • Reinforcement-Steel Fiber Concrete Shield Segment Normal Section Bearing Capacity and Reinforcement Determination Method
  • Reinforcement-Steel Fiber Concrete Shield Segment Normal Section Bearing Capacity and Reinforcement Determination Method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0077] Determination of the bearing capacity of the normal section of the steel-steel fiber reinforced concrete shield segment.

[0078] The steel bar-steel fiber reinforced concrete shield segment normal section load-bearing capacity determination method provided by the present embodiment comprises the following steps:

[0079] S1 Through the three-point bending test of the steel fiber reinforced concrete shield segment opening beam, the elastic bending and tensile residual strength value f under different opening displacement CMOD is obtained R .

[0080] The three-point bending test of the open beam of steel fiber reinforced concrete is specifically to pour different amounts of steel fiber reinforced concrete into a 150mm×150mm×550mm specimen (the weight of steel fiber doping in each cubic steel fiber reinforced concrete is 25Kg / m 3 、30Kg / m 3 、35Kg / m 3 、40Kg / m 3 、45Kg / m 3 、50Kg / m 3 and 55Kg / m 3 ), the steel fiber length is 50mm. like figure 1 As shown, do slotting ...

example 1

[0086] Example 1, for steel fiber doping amount is 30Kg / m 3 The test piece (referred to as test piece SF30), calculated according to the formula (1), f R1 =5.87MPa, f R3 =4.88MPa, therefore, f R3 / f R1 =0.831, the specimen is post-crack softening constitutive model.

example 2

[0087] Example 2, for steel fiber doping amount is 40Kg / m 3 The test piece (referred to as test piece SF40), its f R1 =6.62MPa, f R3 =7.04MPa, therefore, f R3 / f R1 =1.063, the specimen is a rigid-plastic constitutive model.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

PUM

No PUM Login to view more

Abstract

The invention discloses a steel bar-steel fiber concrete shield segment normal section bearing capacity and reinforcement measuring method, which is characterized by taking an elastic flexural-tensileresidual strength value obtained through an open beam three-point bending test as a basic parameter of a material constitutive model, converting the elastic flexural-tensile residual strength obtained by the test into axial-tensile residual strength under a constitutive model; determining the axial force and the bending moment of the steel fiber reinforced concrete on the normal section of the shield segment according to the tensile strength and the stress distribution function of the steel fiber reinforced concrete; and then, considering steel bar configuration, establishing a steel bar-steel fiber concrete shield segment normal section ultimate bearing capacity balance equation set, and determining ultimate bearing capacity or steel bar configuration on the shield segment normal section. Therefore, the method not only can be used for determining the ultimate bearing capacity, but also can be used for determining the steel bar configuration, a steel bar-steel fiber reinforced concrete structure normal section bearing capacity measuring and calculating system is further perfected, and full exertion of the advantages of the steel bar-steel fiber reinforced concrete structure and application and popularization in other fields are facilitated.

Description

technical field [0001] The invention belongs to the technical field of tunnel engineering, and relates to the measurement of the bearing capacity of a shield tunnel segment in tunnel engineering, in particular to a method for measuring the bearing capacity of a front section of a shield tunnel segment and reinforcement in consideration of the post-crack strengthening and toughening mechanism of steel fiber concrete. Background technique [0002] The shield construction method is that the tunnel boring machine builds (lays) the "shield" (referring to the supporting segment) of the tunnel while driving. The lining of shield tunnels mostly adopts ordinary reinforced concrete segments. The reinforced concrete segments have reliable mechanical strength, good corrosion resistance, and mature construction technology. However, large steel consumption, low production efficiency, and It is prone to problems such as brittle failure and high local damage rate. The addition of steel fib...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to view more

Application Information

Patent Timeline
no application Login to view more
Patent Type & Authority Patents(China)
IPC IPC(8): G01N3/08G01N3/20
CPCG01N3/08G01N3/20
Inventor 李德明徐振邓一三殷险峰陈代秉王彬尹静张世杰詹谷益温书亿
Owner 中铁科学研究院有限公司
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products