Shotcrete Layer Research Articles

Experimental study on the pullout behavior of steel rebars in masonry shotcreted layer

Unreinforced masonry (URM) buildings are quite popular worldwide due to their low construction costs, despite being susceptible to significant damage even from moderate earthquakes. In many cases, reconstruction may not be the most viable option due to financial and time constraints. Among the available retrofit solutions, steel-reinforced shotcrete (SRS) proves to be a cost-effective, straightforward, yet effective method for repair/retrofitting. This paper presents the results of an experimental study aimed at evaluating the effects of various construction conditions on the rebar pullout resistance of steel-reinforced shotcrete used as a retrofit method for URM walls. To achieve this, a total of 46 full-scale URM specimens were manufactured and tested, each consisting of a one-sided 50 mm-thick shotcrete layer with a single 8 mm steel rebar. The variables examined included the condition of the URM surface before the shotcrete application (wet/dry, with/without finishing including plaster/scratched plaster/oil paint), the condition of the rebar surface (rusty/clean), the type of rebar (plain/ribbed), rebar cover in the shotcrete layer (20/25/30 mm), and the URM substrate temperature before application of shotcrete (20 °C/-16 °C). The results indicate that there is an increase in pullout resistance of the specimens under the following conditions: when the wall's finishing is removed, the wall's surface is wetted before shotcrete application, ribbed steel rebar is utilized, and the temperature of URM before shotcrete application is 20 °C, there is an increase in pullout resistance of the specimens by 58 %, 56 %, 32 %, and 13 %, respectively. Additionally, when the steel rebar cover is sufficient, ribbed steel rebar is utilized, and this rebar is rusted, there is an increase in pullout resistance of the specimens by 55 %, 10 %, and 6 %, respectively.

Large-scale model test study of the mechanical characteristics on sprayed ECC layer of highway tunnel under confining pressure

As the geological environment of highway tunnels becomes increasinlgy complex, sprayed engineered cementitious composites (ECC) has broad application prospects in the field of highway tunnel support. This study focuses on the shotcrete layer in the initial support of Wulingtou extra-long highway tunnel, the 1:4 scale model test of sprayed ECC layer under confining pressure was prepared. Its mechanical properties and real-time joint monitoring are determined using strain gauges, distributed optical fibers, and cameras. The results show that the maximum confining pressure of the sprayed ECC layer is 0.975 MPa with the maximum displacement of 15.497 cm, which outperforms ordinary shotcrete. The loading process of steel bars and sprayed ECC can be divided into three stages, with the change rate of these three stages showing an ascending trend. The failure mode is ductile, involving normal section, oblique section compression shear failure and bending shear failure. In addition, based on the similarity theory, the real mechanical characteristics of the sprayed ECC layer at the tunnel site can be predicted according to the experimental model.

Effects of granite stratum with different weathering levels on water discharge in metro tunnels

This paper proposes a method for calculating the water discharge in metro tunnels considering limited drainage. With this method, groundwater resources and vegetation can be protected on the premise of ensuring the structural safety of tunnel linings. The water discharge in drainage-limited tunnels constructed through weathered granite was investigated. The water discharge characteristics were explored under different parameters of the shotcrete layer and grouting ring. The effects of the thickness and permeability coefficient of the weathered granite strata on the water discharge in the tunnel were discussed and the results were validated by in-situ monitoring of the water discharge. The results showed that the water discharge decreases with the increase in the thickness ratio of the grouting ring and shotcrete layer and with the decrease in the permeability coefficient ratio of the shotcrete layer and grouting ring. The water discharge can be effectively reduced by increasing the thickness or decreasing the permeability coefficient of the grouting ring. Once the ratio of the grouting ring to the thickness of the shotcrete layer exceeds 20, the water discharge no longer decreases significantly, and by tuning the parameters of the grouting ring, tunnel construction costs can be reduced without affecting the groundwater resource or vegetation around the tunnel. The proposed method can serve as a basis for regulating the water discharge in tunnels located in ecologically fragile regions.

Experimental study on the mechanical properties of FRP reinforced shotcrete lining of tunnel in extremely fractured surrounding rock

Tunnel excavation in the southwestern area of China encounters many difficulties caused by the large deformation of extremely fractured surrounding rock, which is the product of high plate tectonic stress. Improving the initial cracking strength and ductility of shotcrete layer is one of the most important means to reduce the frequency of support structure repair, which will improve tunnel construction efficiency and ensure personnel safety. In this case, this paper introduced fiber reinforced polymer (FRP) mesh to replace the steel mesh as reinforcement to optimize the support effect of shotcrete lining. Both large-scale model test and mechanical test are conducted to compare the reinforcement effect between FRP and steel mesh. Research results indicate that replacing steel mesh with FRP can increase the ultimate deformation capacity of tunnel lining by more than four times. The parametric analysis results indicate that increasing the lining thickness, the diameter of the FRP bars and the mesh density have different degrees of effect on improving the stiffness and strength of tunnel lining. The research results can provide reference for relevant projects.

Study on the influence law of cavities behind the shotcrete lining on the lattice girders

The field monitoring data showed that a small amount of main reinforcement bars of lattice girder at the arch of a tunnel were pulled, and the calculation showed that the initial support structure should be compressed. To find out the reason for the tension of the main reinforcement, the geological radar was used to detect the cavity in the sprayed concrete layer at the tension position. In order to clarify the tension mechanism of the main reinforcement and the influence of factors such as the position and size of the cavity on the main reinforcement, numerical simulations were carried out. The results show that the cavity causes the eccentric compression of the shotcrete layer, resulting in moment of the lattice girder and the change of the stress distribution of the main reinforcement. The main reinforcement experiences tensile stress when the cavity size surpasses 3 m × 0.2 m, reaching a tensile stress of 81 MPa at a cavity size of 6 m × 0.2 m. Notably, the cavity located at the foot of the arch is more likely to produce substantial tensile stress on the primary reinforcement compared to those at the arch crown and waist. The research results provide a theoretical basis for the interpretation and analysis of tunnel lattice girder monitoring data.

Tool developments for additive manufacturing processes with anchor for the modern flow production

AbstractIn modern flow production, the focus is on the continuous digitally controlled tools within the context of the digital twin. Spray extrusion, especially in combination with a thin layer of shotcrete and ribbed supporting structures, for example for facade elements, leads to very efficient components with high load‐bearing capacity and high quality surfaces. The developed combined spray extrusion nozzle offers the possibility of both: spraying and extruding, adapting mortar and concrete. In addition, automated integration of anchors is the focus of flow production, for which anchors and tooling systems have been developed. Based on the determination of characteristic values, the practicability and the increase in productivity could and will be proven. This data forms the basis of a digital twin in preparation for Industry 4.0. This increase in productivity in additive manufacturing leads to positive economic effects, applications of high strength lightweight structures in construction are becoming more attractive and enable the series implementation of free form modular constructions.

Control Mechanism and Support Technology of Deep Roadway Intersection with Large Cross-Section: Case Study

Conventional bolt–shotcrete support technology is usually single-layered, which does not meet the requirements of strength and stiffness for roadway support. Therefore, in this paper, new combined support technology, including a multiple-layered staggered dense arrangement of bolts, multiple-layered laying of steel meshes, multiple-layered pouring of shotcrete, strengthening support of long cables, and full cross-section grouting, is proposed. Specifically, the following new combined support technology process is proposed: first layer of shotcrete (80 mm), first layer of mesh, first layer of bolt, second layer of shotcrete (50 mm), second layer of mesh, second layer of bolt, reinforced cable, third layer of shotcrete (50 mm), and grouting. The results show the following: (1) In the system of a superimposed coupling strengthening bearing arch, compared to a cable bearing arch, changing the support parameters of the bolt bearing arch can significantly vary the bearing capacity. A range of bolt spacing between 0.4 m and 0.7 m is more conducive for a high performance of the bearing capacity of the superimposed coupling strengthening bearing arch. (2) With the increase in the single-layer shotcrete thickness (from 50 mm to 100 mm), the bearing capacity of the shotcrete structure increased rapidly in the form of a power function. (3) After the multi-level bolt–shotcrete support structure was adopted, the ring peak zone of the deviatoric stress of the surrounding rock at the roadway intersection was largely transferred to the shallow part, and the plastic zone of the surrounding rock of the roadway was reduced by 43.3~52.3% compared to that of the conventional bolt–shotcrete support. The field practice model showed that the final roof-to-floor and rib-to-rib convergences of the roadway intersection were 114 mm and 91 mm after 26 days, respectively. The rock mass above the depth of 3 m of the roadway’s roof and sides was complete, the lithology was dense, and there was no obvious crack. The new technology achieves effective control of a deep roadway intersection with a large cross-section.

High-speed train induced vibration measurements in fresh tunnel shotcrete layer

Existing coastal railway track has been undergoing for renovation and improvement work aiming to raise train speed and shorten the travel time between Turku and Helsinki. The track has 16 existing tunnels of which 14 has been renovated between 2019 and 2021. Majority of the tunnels have been reinforced by system and shotcrete and rock bolts. The water seepage control has been solved by using PE sheets with additional 100 mm fibre shotcrete layer as fire protection layer. After the track and tunnel improvements, the track was test driven with two different trains: a high speed SM train unit and a two storey intercity train unit. The speeds used were higher than the current allowed speeds aiming to study the potential to increase the travel speed. One of the most restrictive parameters for the increase is the pressure shock of high speed train entering the tunnel. Too high pressure shock will cause inconvenience for the passengers and can cause damage in tunnel lining structures. Also currently no clear guideline exists what speed limits need to be used for trains entering tunnels with curing shotcrete. To study these matters the test run train units were instrumented including with pressure sensors. The conclusions about the pressure shocks are investigated briefly in the paper.

Flexural Performance of RC Beams Strengthened with Pre-Stressed Iron-Based Shape Memory Alloy (Fe-SMA) Bars: Numerical Study

The iron-based shape memory alloy (Fe-SMA) has promising applications in strengthening and repairing aged steel-reinforced concrete structural elements. Fe-SMA bars can produce pre-stressing forces on reinforced concrete members by activating their shape memory phenomenon upon heating. This study aims to numerically evaluate the impact of pre-stressed Fe-SMA bars on the structural behavior of reinforced concrete (RC) beams at the serviceability and ultimate stages. Nonlinear finite element (FE) models were developed to predict the response of RC beams externally strengthened with Fe-SMAs. The model shows to correlate well with published experimental results. A parametric investigation was also carried out to examine the effect of various concrete grades, pre-stressing levels, and Fe-SMA bars’ diameter on load-deflection behavior. In light of the innovative nature of the Fe-SMA strengthening technique, a comparison investigation was established between RC beams strengthened with Fe-SMA bars against different pre-stressing systems, such as carbon fiber reinforced polymer (CFRP) bars, glass fiber reinforced polymer (GFRP) bars, and steel strands. The numerical findings showed a significant increase in the beams’ load-carrying capacity with larger Fe-SMA bars’ diameter. Specifically, using 12 mm Fe-SMA bars instead of 6 mm increased the beam’s strength by 73%. However, a 14% reduction in ductility was recorded for that case. Moreover, the pre-stressing level of Fe-SMA bars and concrete grade showed a negligible effect on the ultimate strength of the examined beams. Moreover, increasing the pre-stressing level and concrete strength significantly enhanced the load-deflection response in the serviceability stage. Furthermore, using 2T22 mm of Fe-SMA bars resulted in a better structural performance of RC beams compared to other techniques with 2T12 mm, with a comparable cost. Thus, it can be concluded that using Fe-SMA bars embedded in a shotcrete layer attached to the beam’s soffit is a viable and promising strengthening strategy. Nevertheless, further experimental investigations are recommended to further ascertain the reported findings of this numerical investigation.

Mechanical performance of shotcrete shell accompanied with steel sets

The appropriate support system for tunnels in squeezing conditions is the hybrid supporting system consisting of steel sets and a shotcrete layer. The stiffness of this hybrid supporting system is variable between two consecutive steel sets, i.e., a greater value in the vicinity of the steel sets than in other locations. This is because, the contribution of steel sets to confine tunnel convergence is not uniform, but depends upon the distance to each steel frame. Accordingly, the tunnel convergence becomes non-uniform between two consecutive steel sets, and a bending moment is developed on the shotcrete layer, which may influence its design.In this paper, an analytical model is presented to simulate the shotcrete performance between two consecutive steel sets. For this purpose, the shotcrete layer is considered a shell fastened by consecutive steel rings. Using the principles of the theory of shells in the axisymmetric condition, it is assumed that the shotcrete is composed of longitudinal elements glued together from their sides. Therefore, the problem is simplified to analyzing continuous beams leaned on consecutive supports but subjected to loading from the radial and tangential directions. By employing the convergence confinement method, the non-uniform displacements are found.The results obtained with this theoretical simulation well agree with those of numerical modeling by FLAC3D. Therefore, the presented theoretical solution can provide a tool for the preliminary design of the shotcrete layer and an initial estimate of its performance to be used in more complicated numerical models. The results show that the non-uniform radial displacement and bending moment enhance by increasing the tunnel depth and decreasing the rock mass quality. As well, as the thickness of the shotcrete increases, the bending moment reduces.

Application of Internet of Things Based on Wireless Sensor in Tunnel Construction Monitoring

In order to solve the problems of insufficient frequency, time-consuming, and labor-consuming of monitoring and measurement in the process of tunnel construction, a tunnel construction monitoring and measurement technology based on Internet of Things is proposed in this paper. This method adopts the basic theory and technology of Internet of Things, analyzes the fit relationship between Internet of Things technology and tunnel construction, uses the comprehensive perception, reliable transmission, and intelligent auxiliary technology possessed by the existing Internet of Things technology system, and has been successfully applied to tunnel engineering. The experimental results show that the contact pressure between the surrounding rock and the initial support on the monitoring and measurement section in the tunnel is zero after the initial support shotcrete is applied. The contact pressure between the surrounding rock and the shotcrete layer at the right arch waist of the left tunnel is the smallest, and the stress in the whole change process is less than 10 kPa. The contact pressure between surrounding rock and shotcrete layer after excavation is divided into three stages. Conclusion. the tunnel construction monitoring and measurement technology based on Internet of Things technology fully realizes the intellectualization and informatization of the construction process, plays a scientific and effective monitoring and early warning role, and reduces the project cost of the whole project, which has a certain engineering value.

Comparison of the condition of steel fiber-reinforced shotcrete with water-glass and alkali-free activators after more than 20 years of service in a subsea road tunnel

The in-service condition of steel fiber-reinforced shotcrete installed more than 20 years ago as single-shell rock support lining in the Nordkapp subsea road tunnel was investigated. The novelty of this study is the comparison of shotcrete with water–glass and alkali-free activators in a saline groundwater environment. The lowest shotcrete density was obtained at joints between two adjacent shotcrete layers. In the case of alkali-free accelerator, ettringite enrichment was observed in these joints. Leaching appeared to be the main degradation mechanism in the outermost 10–15 cm towards the traffic room.

Analysis of the deformation mechanism and stability of bedding soft rock slope

The lithology of the inlet side slope of the diversion tunnel on the right bank of Wudongde Hydropower Station is dominated by thin marbled dolomite. During construction, numerous cracks form along the elevation direction, and large monitoring deformation values appear in the consequent slope section. In this study, engineering geological analysis, deformation monitoring data analysis, and three-dimensional numerical simulation are combined to investigate the formation mechanism of cracks, the range of local deformed bodies, and the deformation and failure mechanism of deformed bodies. The stability of the slope is rechecked via the rigid-body limit equilibrium method based on the above analysis. Results show that the local convex terrain in the consequent slope section is cut through unfavorable structural surfaces and form a deformable body. Under the influence of unfavorable factors, such as the bedding cut foot caused by the lower excavation unloading and rainfall, the deformation of the shallow slope surface continuously increases; as a result, the shotcrete layer cracks. The deformation force comes from the middle and rear parts of the slope, and the instability mode slides along the bottom boundary level. After prestressed cables are added, the safety factor of the deformed part can satisfy the code requirements, and the existence of the deformed part does not affect the overall slope stability. Therefore, this study can provide technical support for engineering construction and a reference for similar slope engineering research.

Experimental Investigation on Mechanical Behavior of Anchor and Shotcrete Support System Under Axial Pull-Out Action

Based on axial pull-out performance tests of anchor and shotcrete support system with three types of plates and two kinds of shotcretes (plain and steel fiber reinforced concrete) conducted by use of the multi-functional testing system. The mechanical behavior of the anchor and shotcrete support system with the different plate and shotcrete such as the pull-out performance of support system, deformation and failure properties of shotcrete was studied and analyzed. Experimental results showed that the relationship curves between elongation and drawing force has three stages, which are elastic, yielding and hardening. Different plate types have obvious influence on the tensile stiffness during the elastic stage. The steel fiber reinforced concrete spray layer can improve the yield strength of rockbolt under the coupling effect by the support system. The strain at the interface between the initial shotcrete layer and surrounding rock mass is greater than that of the external surface of the resprayed shotcrete layer, though they are equal far away from the rockbolt hole. The shotcrete strain values of steel fiber reinforced concrete is lower than that of plain concrete, and the shotcrete strain values decreases with the improvement of steel fiber content. For shotcrete strain values on the same position, the higher they are the steel fiber content, the lower their strain will be. The failure of plain shotcrete usually begins around of rockbolt hole, when the interfacial stress between the initial shotcrete layer and surround rock is higher than that in the initial shotcrete layer and resprayed shotcrete layer. The steel fiber can effectively improves the toughness, anti-cracking performance and prevent fracture of shotcrete from failure properties. The research results can provide reference for the design and construction of anchor and shotcrete support structure in underground engineering.

Compressive Test Characteristics and Constitutive Relationship of Wet Polypropylene Macrofiber-Reinforced Shotcrete

Shotcrete is often subject to poor ductility and cracking problems, particularly under high stresses. In order to deal with these issues, the feasibility of adding polypropylene macrofibers to shotcrete was verified. To ascertain the supporting effect, dry shotcrete, wet shotcrete, and wet polypropylene macrofiber-reinforced shotcrete (WPMS) were used as samples. Furthermore, the mechanical response characteristics thereof in uniaxial compression tests were compared and analyzed by acoustic emission (AE) monitoring. The results showed that the three materials were brittle, but the ductility, residual strength, and bearing capacity of polypropylene macrofiber-reinforced shotcrete were significantly enhanced. The energy absorption value of plain shotcrete was higher in the cracking stage, while that of polypropylene macrofiber-reinforced shotcrete was greater in the postpeak stage, which showed that the polypropylene macrofiber-reinforced shotcrete had the characteristics of a high crack-initiation strength and toughness. Besides, the energy release from fiber shotcrete occurred after the peak stress rather than near the peak stress. The average energy absorbed by polypropylene macrofiber-reinforced shotcrete was significantly higher than that in dry shotcrete and wet shotcrete, which implied that polypropylene macrofiber-reinforced shotcrete could mitigate the brittle instability of a shotcrete layer. A constitutive model of damage statistics was established based on the test data. The comparison between the experimental data and the fitting results can reflect the characteristics of the total stress-strain curve of such shotcrete. The results provide a basis for the optimization of polypropylene macrofiber-reinforced shotcrete layers.

Bearing Capacity of Concrete Filled Steel Tube Circular Arch under the Six‐Point Uniformly Distributed Loading and Its Engineering Application

The influence of rise‐span ratio on the bearing performance of concrete filled steel tube (CFST) circular arch was studied in this paper, three groups of CFST circular arch specimens with different rise‐span ratios (0.154, 0.207, and 0.26) were selected, the six‐point uniformly distributed loading was performed, and bearing performance experiments on CFST circular arch specimens with fixed ends were carried out. In this study, the ultimate bearing capacity and deformation failure characteristics of CFST circular arch specimens were obtained. The comparative analysis shows that the deformation evolution of CFST circular arch specimens has experienced compaction stage, elastic stage, elastic‐plastic stage, and plastic stage. In the elastic‐plastic and plastic deformation stages, the circular arch shows good ductility and bearing capacity. The bearing capacity of the circular arch is significantly affected by the rise‐span ratio. Compared with circular arch specimens with a rise‐span ratio of 0.154, the yield load of specimens with a rise‐span ratio of 0.207 and 0.26 is increased by 50.8% and 61.5%, and the ultimate bearing capacity is increased by 42.7% and 68.3%, respectively. The larger the rise‐span ratio, the greater the yield load and ultimate bearing capacity of the specimen and the stronger the deformation resistance of circular arch. The numerical simulation on the bending resistance process of circular arch was performed by ABAQUS to present the compression failure process of steel tube and core concrete. The simulation results are in good agreement with the experimental results. The experimental and simulation results show that the circular arch first yields at the inner side of the arch foot, and the curvature of different positions of the specimen is no longer consistent. When the ultimate bearing capacity is reached, the steel pipe at the arch foot obviously heaves, and the hooping effect of the steel pipe on the concrete is invalid. Based on the above research results, a closed composite support scheme of “bolt mesh shotcrete + vertical elliptical CFST support + steel fiber concrete shotcrete layer + reinforced anchor cable” was proposed for the extremely soft rock roadway and successfully applied in the Qingshuiying coal mine.

Application of Shotcreting for Restoring the Working Layer of PAO MMK Oxygen-Converter Workshop Steel-Pouring Ladle Lining

A method for shotcreting steel-pouring ladles under PAO MMK oxygen-converter workshop (OCW) conditions is described. Tests are conducted in the period 2018 – 2020. Results of the work performed are identification of operating parameters that affect wear of the working layer of the lining of steel-pouring ladles beneath the shotcrete layer, prospects for maintaining the lining by shotcreting in order to reduce lining working layer wear and as a result increase the life of PAO MMK OCW steel-pouring ladles.

RC Structures Strengthened by an Iron-Based Shape Memory Alloy Embedded in a Shotcrete Layer-Nonlinear Finite Element Modeling.

Shape memory alloys (SMAs) have been widely used in civil engineering applications including active and passive control of structures, sensors and actuators and strengthening of reinforced concrete (RC) structures owing to unique features such as the shape memory effect and pseudo-elasticity. Iron-based shape memory alloys (Fe-SMAs) have become popular in recent years. Use of iron-based SMAs for strengthening RC structures has received attention in the recent decade due to the advantages it presents, that is, no ducts or anchor heads are required, friction losses do not occur and no space is needed for a hydraulic device to exert force. Accordingly, Fe-SMAs embedded in a shotcrete layer have been used for pre-stressing RC beams at Empa. The aim of this study is to present an approach to model and analyze the behavior of RC members strengthened and pre-stressed with Fe-SMA rebars embedded in a shotcrete layer. The lack of research on developing finite element models for studying the behavior of concrete structures strengthened by iron-based shape memory alloys is addressed. Three-dimensional finite element models were developed in the commercial finite element code ABAQUS, using the concrete damaged plasticity model to predict the studied beams’ load–displacement response. The results of the finite element analyses show a considerably good agreement with the experimental data in terms of the beams’ cracking load and ultimate load capacity. The effects of different strengthening parameters, including SMA rebar diameter, steel rebar diameter and pre-stressing force level on the beam behavior, were investigated based on the verified finite element models. The results were compared. The load-displacement response of an 18-m concrete girder strengthened and pre-stressed with iron-based SMA bars was examined by the developed finite element model as a case study.

Study on support characteristic curve of primary support structures in underground excavation considering bond-slip behavior

Steel reinforced shotcrete lining (SRSL) support is the primary structure to maintain the stability and mobilize the self-bearing capacity of surrounding rock. However, the structural design of SRSL in underground excavation still relies on experience-based method and lack of quantitative mechanical analysis. This paper aims to propose a modified analytical model of support characteristic curve (SCC) that represents the mechanical behavior of SRSL structures in underground construction, through which the interface bond-slip behavior between steel arch and shotcrete layer is taken into consideration. Four-point bending test of SRSL composite beam was carried out to study the bearing mechanism and failure performance. Test results show that the shotcrete-steel interface is prone to slip failure which significantly reduces the overall strength of SRSL. The laboratory test is complemented by non-liner finite element parametric studies considering the bond-slip properties to clarify the design principles and to obtain the flexural stiffness of tunnel primary lining structures. Based on above studies, the simplified formulas for the SCC of SRSL is constructed. The research results provide a theoretical basis for the design and application of SRSL structure in related projects.

Preliminary Design and Cross-Sectional Form Study of Closed-Type Concrete-Filled Steel Tube Support for Traffic Tunnel

In view of the structural form and common construction methods of traffic tunnels, the bearing performance of the closed-type CFST support designed for traffic tunnels is studied. The closed-type CFST support, which consist of a CFST girder with external shotcrete, is improved from the CFST support used in mine roadways. The reasonable cross-sectional form of closed-type CFST support is analyzed by the FEM. The closed-type CFST support is mainly composed of CFST arches, a shotcrete layer, sleeves, and blind flanges. The post-buckling analysis of the closed-type CFST circular arch members using circular-shaped, rectangular-shaped, triangular-shaped, and trapezoidal-shaped steel tubes is implemented. The result shows that the closed-type CFST support has better performance than the traditional tunnel support. The study also found that for closed-type CFST support, the triangular-shaped steel tube section has the highest bearing capacity, stiffness, and steel utilization rate, which is the preferred cross-sectional form. The bearing capacity of the circular-shaped steel tube section is acceptable. Moreover, the circular-shaped steel tubes are more convenient to obtain and process, so it is also an optional cross-sectional form. The square-shaped and trapezoidal-shaped steel tube sections have neither performance advantages nor economic efficiency, so these two forms are not recommended.