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The pipe-jacking inertial guidance method is a key technology to solve the guidance problems of complex pipe-jacking projects, such as long distances and curves. However, since its guidance information is obtained by gyroscope integration, the accrued error is significant, which limits its application. The pipe-jacking construction process has two working modes of static and jacking. The accumulated errors of static state can be corrected with zero velocity to suppress the system position dispersion. Therefore, zero-velocity detection is required. However, the pipe-jacking velocity is so slow (1-2 m/h) that the traditional threshold-based zero-velocity detection method cannot accurately detect the zero-velocity interval (ZVI). Bidirectional long short term memory (Bi-LSTM) can effectively extract the features of repetitive and regular movements during the long-time pipe-jacking construction process. Therefore, this research proposes a working pattern detection model for pipe-jacking based on Bi-LSTM deep learning framework. Through establishing a data collection system to construct the data set and training the model, the accuracy of the test set reaches 98.54%. In addition, a zero-velocity correction model is established. According to the zero-velocity detection results of the Bi-LSTM model, zero-velocity correction is performed. Subsequently, an experimental platform is established to simulate a curve pipe-jacking and attitude experiments. The attitude experiment proves that the proposed model detects the ZVI accurately. The inclination error is corrected by 0.06 °, and the azimuth error is corrected by 0.18 °. Finally, the proposed model is validated by the crossing project of the China-Russia Eastern Natural Gas Pipeline, and the results show that the proposed model effectively detects the working pattern of pipe-jacking machine with strong robustness and adaptability. In summary, the method can effectively improve the detection accuracy of the pipe-jacking working pattern. It lays the foundation for the application of the inertial guidance system in complex pipe-jacking, such as long-distance and curved projects.

To reveal the mechanical response mechanism of bolted connections during the jacking construction of prefabricated utility tunnels, this study combines field monitoring and numerical simulation based on the utility tunnel project in Xiong'an New Area. The evolution characteristics and spatial distribution patterns of bolt stress are systematically investigated. The results indicate that during the jacking and unloading stages, bolt connection stress exhibits a V-shaped spatial distribution with opposite evolutionary trends. This reflects both the weakening effect of transient construction loads on the connection system and the self-recovery characteristics after unloading. Segments at the launching stage experience the most complex loading conditions, with bolt stress displaying a nonlinear W-shaped gradient distribution. The mechanical mechanism transitions from being jacking-load dominated to stratum-load dominated as construction progresses. The distribution of bolt stress shows pronounced non-uniformity, with higher values at the upper edge and lower values at the lower edge. Compared to the lower edge, bolt stress at the upper edge of segments 1-5 attenuates by an average of 25.52-37.63%. This non-uniformity results from the coupled effects of ground friction, which dissipates jacking stress at the bottom while inducing forward tilting of the upper structure, thereby causing greater compression and rebound of the waterproof rubber strip at the upper edge. The non-uniformity coefficient decreases linearly with construction progress, reflecting a transition from an unstable to a uniformly stressed state. The cumulative effect of jacking load exhibits stagewise attenuation along the utility tunnel. In segments 1-2, significant strain concentration occurs, with peak compressive and tensile strains. In segments 3-4, direct jacking influence weakens, but delayed strain deterioration is observed, with maximum compressive strain reaching only 69.72% of that in the initial stage. By segment 5, the jacking effect attenuates to background levels. The relationship between bolt stress and jacking spacing follows an exponential decay function. Bolt stress during the loading stage is approximately 76.99-89.07% of that during the unloading stage. Deformation at the roof is significantly greater than that at the floor and sidewalls, consistent with bolt stress distribution patterns.

The capacity of the coastal drainage network is significantly reduced by the jacking effect of high tide and river levels under compound flooding, but the mechanism of jacking effect on drainage network is not fully understood. In this study, the jacking effect of high tide and river levels is analyzed based on physical and numerical models using Haikou City as an example. A physical model for simulating compound flooding is constructed based on kinematic similarity, dynamic similarity and geometric similarity, and a numerical simulation model is constructed based on the PCSWMM model. The process and characteristics of jacking effect under high tide and river levels and the flow inter-feedback between tide-river-drainage network are evaluated using physical and numerical models coupled with water tracer method. The results show that the physical and numerical models constructed in this study have high simulation accuracy. The influence extent and intensity of the jacking effect on the drainage network will show a weakening trend with the increase of rainfall intensity, and the percentages of pipeline affected by jacking effect under the 50-year rainfall and 20-year rainfall are 52.6 % and 60.9 %, respectively. The jacking effect of high tide level is more obvious at downstream outfall, and the jacking effect of high tide and river levels interact with each other and show an inverse correlation. This study provides a theoretical basis for quantifying the jacking characterization of high tide and river levels on drainage networks and the occurrence mechanism of compound flooding.

Pipe jacking in water-rich sandy strata is frequently suffered by rapidly increasing seepage-induced hazards (e.g., groundwater inrush at working shafts) in jacking lubrication, which is because their limited anti-seepage capacity of conventional bentonite-based lubricants. In order to enhance the lubrication and anti-seepage performance of lubricants along the pipe-soil annulus, this study developed a composite agent with anti-seepage and friction reducing, where graphite(SM) is used as lubrication, Na2CO3 is used as dispersibility, polyacrylamide(PAM) is used as thixotropy, polyisocyanates and polyols are used as primary agents, triethanolamine(TEA) and dibutyltin dilaurate (DBTDL) are used as catalysts, and sodium silicate is used as water resistance due to the gelation effect at lower temperatures. The preparation method of the composite anti-seepage and friction reducing agent was investigated, and its macro- and micro-scale performance tests were conducted. Additionally, the optimal mix ratio was determined using the range analysis method and entropy weight method. The research indicates that the optimized composition of the composite anti-seepage and friction reducing agent is as follows: SM(0.8%-1.0%), PAM (2.0%-2.5%), Na2CO3 (0.3%-0.5%), DBTDL (1.4%-1.6%), TEA(1.0%-1.5%), and Na2O·3.1SiO2 (15%-20%). Compared to traditional bentonite-based friction reducing agent, the funnel viscosity range is reduced by 55%, the filtration loss range is reduced by 25%, the water separation rate is decreased by 4.5% (approaching 0), the friction coefficient is lowered by 20% ~ 28%, and the permeability coefficient reaches 3.5 × 10-⁵-5.0 × 10-⁵ cm/s. This paper addresses the issues of high frictional resistance and difficult waterproofing in jacking construction through water-rich sand stratum. The proposed preparation process of composite agent provides an essential material of practical route for reducing jacking forces and eliminating water inrush risks during pipe jacking in water-rich sandy strata.

With its advantages of high cross-sectional utilization, shallow depth, and uninterrupted surface road traffic, the pipe-jacking method has been widely used in underground passages, metro stations, and other projects. However, this leads to a large volume of pipe-jacking waste soils that must be processed. Pipe-jacking waste soils are different from shield-tunneling waste soils. Therefore, it is not appropriate to simply use the same treatment method for shield-tunneling waste soils in the treatment of pipe-jacking waste soils. In this study, pipe-jacking waste soil samples were improved with 7% polyacrylamide (PAM) and 12% sodium-based bentonite solutions, with good performance being achieved. Based on this, quick lime and fly ash were used in the solidification of pipe-jacking waste soils, and experiments with different solution concentrations and solidification material additions were conducted, involving tests of compression, freeze-thaw cycling, wet-dry cycling, and microstructure. The results indicate that within the ranges of PAM and sodium-based bentonite addition ratios applied in this study, the solidification effects of quick lime and fly ash will not be significantly reduced during the improvement processes of pipe-jacking waste soils under balanced earth pressure conditions. Instead, it was found that there was an increase of up to 16% in the strength of pipe-jacking waste soils. Structural compactness can be primarily enhanced by gelatinous PAM, while sodium-based bentonite can promote the formation of hydrated colloids (such as C-S-H) and fill soil pores with hydrated gelatinous bentonite particles, thereby enhancing soil stability.

During shield tunnelling, vertical ground displacement is significantly influenced by deviations in both jacking force and cutterhead torque. This study investigates the effects of deviations in these parameters on ground displacement via numerical simulations. On the basis of measured data from the Zhubai-Longgang Sewage Connecting Pipeline Project in Shanghai, a parametric analysis was conducted with ABAQUS software to simulate the effects of deviations in jacking force and cutterhead torque on vertical ground displacement. The results indicate that a positive deviation in jacking force increases the arch ratio (R) ahead of the shield cutterhead, leading to greater ground heave. Additionally, the positive area of the arch ratio contracts towards the tunnel's central axis with increasing cutterhead torque deviation, further increasing ground heave. The study also revealed that cutterhead torque deviation has a more pronounced effect on ground heave than does jacking force deviation. The maximum ground heave converges when the cutterhead torque deviation extends over an 8-ring distance, while this result occurs when jacking force deviation extends over a 1-ring distance. When the deviations in both jacking force and cutterhead torque are combined, the maximum ground heave is the linear superposition of the independent effects of each parameter. The relationship between the combined deviation distance and the maximum ground heave can be expressed with a power function.

In practical engineering, whilst estimating the jacking force of rectangular pipe jacking using an empirical formula, the results obtained from said formula deviate from reality and manifest inadequate engineering guidance. The equations governing the applied force during the installation of rectangular pipe jacking have been derived for various contact states involving the interaction between the pipe, slurry, and soil. The distinct stress conditions in the pipe jacking process as well as the shear-friction mechanism between the pipe and the surrounding soil have been taken into account. The displacement control method is introduced to simulate the pipe-slurry-soil contact friction during the pipe jacking process in FLAC3D. Additionally, the pipe jacking behavior, pipe-slurry-soil contact frictional force, and variation law of the jacking force are also simulated. Mutual verification was carried out using the results obtained from field monitoring, numerical and theoretical. The findings are as follows: the established equations for calculating pipe jacking force are highly applicable across various conditions of pipe-slurry-soil contact, and the outcomes derived from theoretical formulas align remarkably well with those obtained through field monitoring and numerical simulation. During the jacking process, the sidewalls exhibit initial partial sliding followed by a complete movement as the jacking force intensifies and subsequently diminishes, eventually attaining stability during the behavior adjustment phase. Moreover, the bottom pipe-soil contact is the most common situation in actual construction.

As an emerging shaft construction technique, vertical pipe jacking significantly influences the surrounding soil deformation. Based on Mindlin's solution and the analogous stochastic medium theory method, this study integrates analytical solutions for soil deformation induced by multiple factors, including additional grouting pressure, the bulkhead additive thrust of the jacking machine, the frictional force between vertical pipe jacking machine and soil, the frictional force between follow-up pipes and soil, and ground loss. A comprehensive calculation formula for soil deformation under multi-factor conditions is derived, and the contribution of each influencing factor is analyzed. The results indicate that the overall trend of vertical displacement in soil is settlement, with the maximum settlement occurring at approximately 0.5 times the pipeline diameter from the pipe jacking centerline. Among the influencing factors, ground loss plays a dominant role in both vertical settlement and horizontal displacement, while other factors have relatively minor effects on soil deformation. Both the burial depth of the utility tunnel and the jacking distance influence soil deformation patterns.

Circular pipe-jacking construction in gravel strata faces significant technical challenges, including high frictional resistance, elevated permeability, and susceptibility to collapse. Optimizing the formulation of thixotropic slurry is crucial for improving the construction quality and efficiency of such projects. This study, based on the Ruyang Water Supply Project of the North Main Canal in the Qianping Irrigation Area, Henan Province, China, systematically investigated slurry formulation using bentonite, soda ash, sodium carboxymethyl cellulose (CMC), polyacrylamide (PAM), and shell powder as raw materials. An orthogonal experimental design was employed to optimize the mix proportions, and the friction-reduction performance was validated through drag-friction model tests. The results indicate that the optimal slurry formulation is: bentonite 8%, soda ash 0.3%, CMC 0.2%, PAM 0.15%, shell powder 4%, and water 87.35%. This formulation exhibits excellent fluidity and thixotropy, facilitating the formation of a stable slurry film. Consequently, the friction coefficient between concrete specimens and gravel soil was reduced by 35.6%. The inclusion of shell powder significantly enhanced the slurry's cohesiveness and improved the anti-seepage capacity of the surrounding stratum due to its filling effect. The optimized thixotropic slurry effectively mitigates frictional resistance during pipe jacking in gravel strata and enhances the formation's resistance to collapse. The findings of this study provide a viable technical reference for pipe-jacking projects under similar geological conditions.

In order to study the railway line deformation and dynamic response of ballastless track structure under train load during jacking rectification fixing, a three-dimensional numerical model of the CRTS II slab ballastless track on subgrade is established by using the finite element method. The line deformation rule and local damage rule of ballastless track under jacking force are analyzed. The dynamic response laws of track structure and subgrade bed are compared considering four different connection modes between the base plate and subgrade bed under different train speeds in the process of jacking rectification fixing. The results show that jacking force and dissociation length have a small influence on the deviation value and the critical jacking force should be smaller than 375 kN in single point jacking. Under the condition of multi-point jacking, when the jacking loading length equals to 5 slabs, the critical jacking force should be smaller than 275 kN and the maximum lateral deviation value is about 22.11 mm. It is necessary to restrict the speed of passing trains to no more than 150 km/h during the jacking rectification fixing for dissociation condition without temporary restraint. When temporary restraint is applied, the speed of the train can be increased appropriately according to the actual situation. The above study results could be used as a theoretical reference for the ballastless track deviation correction.

An inertial guidance system based on a fiber optic gyroscope (FOG) is an effective way to guide long-distance curved pipe jacking. However, environmental disturbances such as vibration, electromagnetism, and temperature will cause the FOG signal to generate significant random noise. The random noise will overwhelm the effective signal. Therefore, it is necessary to eliminate the random noise. This study proposes a hybrid de-noising method, namely complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN)-lifting wavelet transform (LWT). Firstly, the FOG signal is extracted using a sliding window and decomposed by CEEMDAN to obtain the intrinsic modal function (IMF) with N different scales and one residual. Subsequently, the effective IMF components are selected according to the correlation coefficient between the IMF components and the FOG signal. Due to the low resolution of the CEEMDAN method for high-frequency components, the selected high-frequency IMF components are decomposed with lifting wavelet transform to increase the resolution of the signal. The detailed signals of the LWT decomposition are de-noised using the soft threshold de-noising method, and then the signal is reconstructed. Finally, pipe-jacking dynamic and environmental interference experiments were conducted to verify the effectiveness of the CEEMDAN-LWT de-noising method. The de-noising effect of the proposed method was evaluated by SNR, RMSE, and Deviation and compared with the CEEMDAN and LWT de-noising methods. The results show that the CEEMDAN-LWT de-noising method has the best de-noising effect with good adaptivity and high accuracy. The navigation results of the pipe-jacking attitude before and after de-noising were compared and analyzed in the environmental interference experiment. The results show that the absolute error of the pipe-jacking pitch, roll, and heading angles is reduced by 39.86%, 59.45%, and 14.29% after de-noising. The maximum relative error of the pitch angle is improved from -0.74% to -0.44%, the roll angle is improved from 2.07% to 0.79%, and the heading angle is improved from -0.07% to -0.06%. Therefore, the CEEMDAN-LWT method can effectively suppress the random errors of the FOG signal caused by the environment and improve the measurement accuracy of the pipe-jacking attitude.

In pipe jacking construction, thixotropic slurry critically governs lubrication, friction reduction, and ground support. This study evaluated slurry performance through six parameters: specific gravity (SG), pH, fluid loss (FL), water separation rate (WSR), filter cake thickness (FCT), and funnel viscosity (FV). Orthogonal experiments optimizing bentonite, carboxymethyl cellulose (CMC), and sodium carbonate (Na2CO3) ratios established 10 wt.% bentonite, 0.3 wt.% CMC, and 0.4 wt.% Na2CO3 as the optimal formulation. Subsequently, to address performance limitations in challenging conditions, this study introduces hydroxyethyl cellulose (HEC) as a novel additive, with potential advantages under high-salinity and variable pH conditions. Comparative experiments demonstrated that HEC, as a non-ionic water-soluble cellulose, not only significantly increases FV and reduces FL while maintaining SG, FCT, and WSR within acceptable thresholds, but also exhibits superior pH stability compared to CMC. Based on the aforementioned results, interface friction characterization tests were conducted on representative slurry formulations with varying FVs, quantitatively demonstrating the viscosity-dependent friction-reduction performance. Complementary scanning electron microscopy (SEM) analysis of three distinct thixotropic slurry compositions systematically revealed their microstructural characteristics, with microscopic evidence confirming the excellent compatibility between HEC and thixotropic slurry matrix. These findings highlight HEC's potential as an effective alternative in pipe jacking, particularly in demanding geological environments.

The pipe jacking guidance system based on a fiber optic gyroscope (FOG) has gained extensive attention due to its high degree of safety and autonomy. However, all inertial guidance systems have accumulative errors over time. The zero-velocity update (ZUPT) algorithm is an effective error compensation method, but accurately distinguishing between moving and stationary states in slow pipe jacking operations is a major challenge. To address this challenge, a "MV + ARE + SHOE" three-conditional zero-velocity detection (TCZVD) algorithm for the fiber optic gyroscope inertial navigation system (FOG-INS) is designed. Firstly, a Kalman filter model based on ZUPT is established. Secondly, the TCZVD algorithm, which combines the moving variance of acceleration (MV), angular rate energy (ARE), and stance hypothesis optimal estimation (SHOE), is proposed. Finally, experiments are conducted, and the results indicate that the proposed algorithm achieves a zero-velocity detection accuracy of 99.18% and can reduce positioning error to less than 2% of the total distance. Furthermore, the applicability of the proposed algorithm in the practical working environment is confirmed through on-site experiments. The results demonstrate that this method can effectively suppress the accumulated error of the inertial guidance system and improve the positioning accuracy of pipe jacking. It provides a robust and reliable solution for practical engineering challenges. Therefore, this study will contribute to the development of pipe jacking automatic guidance technology.

In trenchless pipe jacking engineering practice, the formation of high-quality slurry jacket on the outer wall of pipe section is the key to effectively reducing the pipe-soil frictional resistance, improving the construction efficiency, reducing the construction risk and ensuring the construction safety. Herein, the multifunctional experimental apparatus for the pipe-soil frictional resistance testing is improved to ensure the smooth implementation of the subsequent experimental research. The influences of the structural parameters of grouting holes in circular and rectangular pipe sections on the pipe-soil frictional resistance and the states of slurry jackets around the various pipe sections are investigated respectively based on orthogonal experiment. Key findings include the pipe-soil frictional resistances increase with the increase of the spacing between adjacent grouting holes and the deflection angle of grouting holes, the layout of grouting holes has the greatest influence on pipe-soil frictional resistance, reasonable and uniform layout of grouting holes around the pipe sections can form more complete high-quality slurry jackets, to show better pipe-soil frictional resistance reduction effect. Moreover, the optimal structural parameters of grouting holes in circular and rectangular pipe sections are the same, i.e. the layout is triple grouting holes, the spacing between adjacent grouting holes S is 417 mm, and the deflection angle of grouting holes α is 40°. These insights could provide some scientific and valuable guidance for pipe-soil frictional resistance reduction during trenchless pipe jacking.

With the rapid urbanization process in China, there has been a significant development of urban underground spaces. The pipe-jacking method has gained popularity in various projects due to its advantages such as short construction period, adaptability to different soil conditions, and minimal excavation disturbance. This study focuses on a tunnel project involving double-hole rectangular pipe-jacking under an expressway. Utilizing FLAC software, a three-dimensional numerical model was created to analyze the impact of double-hole pipe-jacking construction on surface settlement and deformation of the expressway. The simulation results were validated by comparing them with field monitoring data. The study also investigated the impact of different construction parameters, such as excavation sequence and the angle of underpassing the expressway, on surface settlement. Additionally, the surface settlement curve at the slope bottom of the expressway exhibits asymmetric distribution and an offset center in the settlement trough. It is recommended to carry out the construction of double-hole pipe-jacking in the sequence of "big first and then small". Furthermore, when the included angle between the expressway and the jacking axis is 90°, the impact on surface settlement is minimized. This research provides valuable insights for the construction of double-hole pipe-jacking underpass structures in tunnel engineering.

In the course of pipe jacking construction, the carrying-soil effect frequently arises, influenced by factors such as excavation unloading, ongoing disturbance from successive pipe sections, and the progressive accumulation of soil adhesion. The pipe jacking slurry serves as a critical agent for friction reduction and strata support, essential for the secure advancement of the construction process. This study introduces the Microbial-Induced Calcium Carbonate Precipitation (MICP) technology into the realm of pipe jacking slurry, aiming to enhance its friction-reduction capabilities and the stability of the soil enveloping the pipe. An optimal MICP-slurry formulation was determined using the uniform design approach. Subsequent model tests were carried out to assess the friction-reducing efficacy of the MICP-slurry, while the mechanism by which the MICP-slurry reinforces strata stability was investigated through soil mechanics and scanning electron microscopy (SEM) analyses. The findings indicate that the optimal MICP-slurry composition is as follows: bentonite: sodium carboxymethyl cellulose: soda ash: polyacrylamide: xanthan gum = 12%: 0.31%: 0.36%: 0.25%: 0.54%. The MICP-slurry achieves a 42.2% reduction in the friction coefficient between the test block and the sand. In comparison with the untreated sample, the cohesion of the MICP-treated sample is enhanced by 38.12%, and the internal friction angle increases by 14.01%. SEM examination reveals that the calcium carbonate crystals precipitated by the MICP-slurry within the soil populate the pores, increase the inter-particle bite force, and bolster the soil's mechanical characteristics.

Traditional rectangular tunnel boring machines have low tunneling efficiency, poor soil mixing effects, which has hindered the construction of long-distance and large-section box jacking projects. To overcome these limitations, a new type of full-face excavation boring machine was developed based on a planetary transmission mechanism. This machine achieves full-face excavation by utilizing three eccentric cutter heads that revolve around both the central axis of the cutter plate and their individual shafts. The design methodology, feasibility, and principles of this new mechanism were introduced. Furthermore, a successful construction project of an underground highway passage in Japan was presented as a case study to demonstrate the design and application of this tunnel boring machine. The case details include the excavation face support mechanism, optimal cutter-head layout, obstacle removal strategies, and methods for reducing jacking resistance. Monitoring data from the project verified the applicability, reliability, and overall engineering performance of the rectangular shield machine developed using the planetary mechanism. This research demonstrates that the planetary transmission mechanism-based boring machine offers superior performance in terms of ground settlement and tunneling speed, potentially providing a comprehensive solution to the challenges in the development of rectangular shield machines for box jacking projects.

This article is based on the relocation project of the 330 kV overhead line in Xi'an, China. In this paper, the soil settlement under different jacking depths was calculated by using the modified Peck's formula. Meanwhile, by modeling in ABAQUS, the jacking process of a single-chamber double-line large diameter pipeline under different soil conditions was simulated, and the ground deformation data under the different simulated working conditions were obtained. The results of the two methods were compared with the construction monitoring results, and it was found that the finite element simulation results were closer to the actual results. The control variable method was used in the analysis of the surface soil deformation law to analyze the effect of different soil parameters and pipe jacking depths on surface soil deformation. Finally, the best soil conditions applicable to single-chamber double-line large diameter pipe jacking construction were obtained through comparative analysis. The results show that (1) when using double-line construction, the maximum surface settlement under different soil conditions is located 11-15 m from the centerline of the soil above the pipeline, the minimum settlement location is inside the isolation pile, and with the increase in jacking distance, the settlement at the same section of the surface will gradually decrease and finally produce a small uplift. (2) In the first jacking, the settlement of powder clay is the largest, and the maximum settlement points in the surface section are more distributed. The maximum settlement value is approximately 11.66 mm. The settlement of powder soil is the smallest but produces a certain uplift deformation, and its maximum settlement is more concentrated in the surface section. After the comparison of deformation and soil parameters, loess-like soil is more suitable for single-compartment double-line large diameter pipe jacking construction. (3) When the top pipe burial depth changes, the greater the burial depth is, the smaller the settlement but the greater the lateral influence range. In the soil parameters, the modulus of elasticity only changes 3 MPa, and the settlement change value is approximately 5 mm. By changing the parameters, it can be obtained that the larger the modulus of elasticity of the soil is, the smaller its deformation. The larger the internal friction angle of the soil is, the smaller its deformation, but the maximum value of settlement change is only 1.7 mm, which means that the change in the internal friction angle has little effect on the soil deformation.

With the continuous construction of urban traffic roads, more and more new roads are cut off by existing roads to form "dead end roads". There is an urgent need for a trenchless method suitable for urban ultra-shallow overburden to build the undercrossing tunnel. To solve this problem, this paper proposed the micro pipe jacking and joint assembly structure (MPJ & JAS) method, which has the characteristics of shallow burial depth, low cost, short construction time, flexible cross-section setting and high space utilization. The MPJ & JAS method construct a large cross-section tunnel through assembling small cross-section elements, quite different from traditional methods. Therefore, this paper designed a CT-shaped integrated joint, the mechanical performance of which was verified and clarified by tensile test. The bending test and finite element (FE) analysis proved the reliability of MPJ & JAS tunnel structure, and confirmed the structure performances such as the failure models, crack behaviors, load-deflection response and stress-strain distribution. Moreover, the influences of the steel plate thickness, concrete strength and shear connector spacing were determined by the FE analysis. On the basis of test results and reasonable assumptions, a theoretical design method considering the influence of the CT-shaped integrated joint was proposed, which can effectively predict the bending strength of the MPJ & JAS tunnel structure with an error of less than 10%. Finally, in view of the characteristics of the MPJ & JAS method, the suitable micro pipe jacking machine, soil reinforcement measure, hydraulic traction construction technology, high-precision guidance system and concrete construction quality detection method based on the phased array ultrasonic imaging technology were developed, supporting the accurate and efficient construction of the MPJ & JAS tunnel.