High Bearing Capacity Research Articles

Study on the Flexural Performance of Ultrahigh-Performance Concrete-Normal Concrete Composite Slabs.

In recent years, there have been an increasing number of examples of using ultrahigh-performance concrete (UHPC) as a pavement layer to form an ultrahigh-performance concrete-normal concrete (UHPC-NC) composite structure to improve the bearing capacity of bridges. In order to study the flexural performance of this kind of structure, this research studied the flexural performance of UHPC-NC composite slabs, with UHPC in the compression zone, using experiments, numerical simulation, and theoretical analysis. The results showed the following. Firstly, after the UHPC-NC interface had been chiseled, there was no obvious slip between the two materials during the test, and the composite plate was always subjected to synergistic stress. Secondly, the composite slabs in the compression zone of the UHPC were all subjected to bending failure, and the cooperative working performance of each part under the bending load was good, indicating that the composite slab had a unique failure mode and a high bearing capacity. Thirdly, increasing the thickness of the UHPC significantly improved the flexural capacity of the composite plate, and the maximum increase was about 15%. Increasing the reinforcement ratio of the tensile steel rebars also had an increasing effect, with a maximum increase of about 181%. Finally, the proposed formula for calculating the flexural capacity of composite slabs with UHPC in the compression zone could accurately predict the bearing capacity of said slabs. The calculated results were in good agreement with the experimental values, and the error was small.

Experimental and numerical analysis of single piled raft unit in unconventional soil

ABSTRACT This article explores the behaviour of single piled raft units and their components (raft and pile) under axial compression through experimental and numerical analysis. Prototypes were constructed and subjected to static load tests in silty-clayey sand subsoil. Piles were instrumented at different depths to analyse load distribution and transfer, showing improved load transfer along the pile length. Compared to single piles and rafts, single piled raft units in tropical soil exhibited approximately 10% and 62% higher bearing capacity, respectively. Experimental data validated a numerical model, indicating a stress bulb behaviour reaching 1.5 to 2 times the raft diameter in the pile region, reducing skin friction along the shaft. The pile-raft connection enhanced structural rigidity, increasing bearing capacity and reducing settlements. These findings underscore the significance of pile-raft interaction for foundation performance and efficiency under axial compression.

Close-in explosion performances and damage evaluation of bamboo fiber reinforced laminates

Three types of laminated bamboo plates (LBPs), namely flat-pressed one-way plate (PR), flat-pressed orthogonal plate (PC), and side-pressed one-way plate (PT), were designed and manufactured to investigate their mechanical responses under quasi-static and blast loadings. The experimental results show that the LBPs have excellent blast resistance. In-field explosion experiments clearly reveal the damage patterns of the LBPs with scaled distance changing from 2.052 m/kg1/3 to 0.054 m/kg1/3. Plates PR and PT have five damage patterns, which are slightly scorched, matrix cracking, fiber breakage, spalling and outbreak-crash, respectively. Plates PC eliminate the matrix cracking damage pattern through balancing the anisotropy by orthogonal structure. After explosion, the LBPs still maintain good elasticity, structural integrity and high residual bearing capacity. The residual bearing capacity of plates PR-1, PT-1 and PC-1 repetitively suffered seven explosions is decreased to 58.8 %, 42.6 % and 68.7 % of the average bearing capacity of the reference plates, respectively. It is concluded that orthogonal and side-pressed structures are conducive to enhance the load carrying capacity of the LBP.

Microstructure and dynamic behaviours of polyurethane-cured sea sand under traffic–load–induced stress path

Employing sea sand as fill material for roadbeds presents significant challenges due to its naturally high dispersibility and low bearing capacity, which contribute to substantial settlement deformations under traffic load impacts. In this investigation, a two-component polyurethane was applied to enhance mechanical properties of sea sand. Alterations in the microstructure and dynamic behaviours of the polyurethane-cured sea sand were observed via Scanning Electron Microscopy (SEM) and hollow cylindrical torsional shear testing. It was found that polyurethane is incorporated into the sea sand as adhesives between particles, attachments on the particles and floating adhesives. With an increase in polyurethane content, a transition from a granular to a solid state in the sand was noted, accompanied by a progressive improvement in structural integrity. This resulted in an enhanced bonding effect at interparticle contacts with diminishing relative particle movements during shearing, leading to an increase in the critical dynamic stress ratio and a decrease in the maximum damping ratio, with both ratios being higher in cured sea sand with lower polyurethane content compared to that with higher content. Additionally, high polyurethane content induced strain hardening in the cured sea sand, resulting in a higher maximum dynamic shear modulus in low-content cured sea sand compared to high-content. Furthermore, the dynamic shear modulus ratio in sea sand with high polyurethane content was found to increase with the number of vibrations.

Performance and behaviour of prebored and precast pile with floating pile tip based on A full-scale field static axial load test

This study investigates the load transfer mechanism of a Prebored and Precast pile (PP pile), constructed installed in accordance with the rules applicable to the Hyper-Straight pile method (HS pile), in clay soils. While the HS pile method, developed in Japan, typically results in high bearing capacity piles in various soil types, its performance in clay soils remains understudied. Our research focuses on a unique configuration where the pile tip “floats” within a soil–cement mixing (SCM) column near the bottom of the borehole, a condition that significantly influences the system’s performance.We conducted a full-scale axial static load test on a 500 mm diameter and 140 mm thickness straight shaft precast prestressed concrete spun pile. The pile was instrumented with vibrating wire strain gauges (VWSG) and displacement measuring devices (tell-tales), embedded 15 m deep in a 750 mm diameter SCM column (15.75 m long). The pile tip was positioned 75 cm above the bottom of the borehole, creating a floating condition within the SCM material. Both the pile and the surrounding SCM were instrumented to provide comprehensive data on the system’s behavior.The test involved two loading–unloading cycles. The 1st Cycle reached a maximum load of 3627 kN, resulting in a 75.52 mm pile head settlement. The 2nd Cycle achieved a maximum load of 4181 kN, leading to a 118.04 mm pile head settlement. In the 1st Cycle, we observed upward movement of the SCM material around the shaft after the pile skin friction reached its maximum capacity. Stress at the pile tip exceeded the unconfined compressive strength of the SCM material, indicating potential local shear failure.Contrary to expectations based on HS pile performance in other soil types, the ultimate bearing capacity of our pile was determined to be 2000 kN, comprising 545 kN from skin friction and 1455 kN from end bearing. This result aligns more closely with the behavior of conventional bored pile rather than the “hyper” capacity typically associated with HS pile. Consequently, we classify our pile as a “prebored and precast pile,” like systems used in China and Korea.Our study concludes that the strength of the SCM material and the pile tip location significantly influence the pile’s bearing capacity in clay soils. These findings highlight the critical impact of soil type on the performance of piles constructed using the HS method. The observed behavior suggests that current design methods for HS pile may overestimate capacity in clay conditions, emphasizing the importance of soil-specific analysis and testing.This research contributes to the understanding of PP pile behavior in clay soils, providing valuable insights for geotechnical engineers. It underscores the need for refined prediction models and design methods specific to these soil conditions, paving the way for more accurate and reliable foundation designs in regions with predominant clay soils.

A novel method for investigating ice-substrate interfacial rheology and long-term adfreeze strength through loading-unloading creep test

Ice cementation and ice-substrate adfreeze force are the primary contributors to the high bearing capacity of pile foundations in cold regions and the stability of frozen walls in areas subjected to artificial freezing. Given the significant temperature sensitivity of ice’s shear rheology, engineering structures in ice or ice-rich soils continue to deform even under constant external loads. A thorough understanding of shear creep and the long-term adfreeze force at the ice-substrate interface is essential for predicting the continuous deformation of these structures. However, research into the shear creep behavior at frozen interfaces has historically been constrained by the precision of temperature control in experimental settings and the complexity of load paths in shear testing devices. In this study, a temperature- and stress-control device for interface shear creep is assembled firstly, and multilevel loading-unloading creep tests on steel pipes embedded in layered frozen ice were conducted. Through the decoupling of deformation progression, the viscoelastic and viscoplastic shear behaviors at the steel-ice interface under various temperatures and shear stresses were characterized, the principle of sustainable interfacial shear creep along with its underlying physical mechanism were proposed. Subsequently, with the aid of a modified nonlinear Burger model, various interfacial shear creep parameters were derived. Results reveal that the interfacial generalized shear modulus continuously improves but with a gradually weakening degree until a point of accelerating creep is reached. Additionally, the long-term adfreeze force is found to be less than half of the short-term strength, which significantly decreases as the temperature approaches the water phase transition zone. Interestingly, the stress exponent associated with the interfacial steady creep rate is considerably smaller than that predicted by Glen’s law. This research provides a theoretical basis instrumental in the engineering design in cold regions and those structures employing artificial freezing techniques.

Axial compressive mechanical behavior of a CFRP-confined composite member composed of bamboo strips and a thin-walled steel tube

To utilize fully the excellent mechanical properties of bamboo, thin-walled steel, and carbon fiber-reinforced polymer (CFRP), a CFRP-confined composite member composed of bamboo strips and a thin-walled steel tube (CBSC) was proposed to design a bamboo member with high-bearing capacity and ductility. The axial compressive tests were conducted on 26 CBSC members. Based on the validated finite-element (FE) model, a parametric analysis was performed to investigate the effects of different parameters on the axial compressive mechanical behaviors of CBSC members. Finally, the predictions of the ultimate axial compressive bearing capacity derived from the unified theory of concrete-filled steel tube columns agreed well with the test and FE results. The results showed that the failure mode of short CBSC members was strength failure, including material damage in the middle of the member, and end-crushing failure. However, the slender CBSC members exhibited typical global buckling failure. CBSC members can fully utilize the mechanical characteristics of the three materials to exert their combined effects. In terms of improving the bearing capacity, the recommended number of CFRP layers for all CBSC members is one except for the short CFRP-confined bamboo strip, thin-walled, circular steel-tube composite members, which is equal to two. The critical slenderness ratios of the CBCSC specimens and CBSSC specimens for distinguishing strength failure and global buckling are 19 and 36, respectively. The proposed predicted equations can accurately estimate the ultimate bearing capacity of CBSC members under axial compression.

The Behavior of the Tunnel Reinforced with Geogrid in Soft Soil Under the Effect of Axial Load

The soft soil's poor tensile strength requires reinforcing to increase bearing capacity, improve stability, and reduce settlements. This study assessed the efficacy of using geogrid layers to enhance and secure the soil surrounding tunnels. enabling the tunnel to endure pressure, particularly during excavation. The utilization of geogrids in soil reinforcement has experienced a substantial rise as a result of their consistent dimensions and exceptional tensile strength. To quantify the exerted force transferred to the tunnel, during this study utilized various testing tools, including a soil container, a steel loading frame, data loggers, a 0.5-ton load cell, and a miniature pressure cell. The vertical loads are applied by utilizing a hydraulic jack. A series of eleven tests were conducted on the tunnel at two depths of 1.5D and 2.5D, where D is the tunnel's diameter. The different models of geogrid layers showed that using two layers of geogrid at the first dimension, 0.5B and 1B from the base, led to a significant increase in tunnel stability. Two layers of reinforcement were used in both directions, giving the soil a high bearing capacity for the loads applied to the tunnel. This resulted in an improvement, a 1.65 in 1.5D and a 1.82 in 2.5D. The pressure above the pipe decreased by approximately 7.1kPa at the first tunnel depth and about 3.5kpa at the second depth. In conclusion, the study found the geogrid improves the stability of the tunnel by equally distributing loads and minimizing stress concentrations, hence decreasing the chances of collapses or deformations. Doi: 10.28991/CEJ-2024-010-08-04 Full Text: PDF

Seismic Performance Analysis of PEC Structures

Partially-Encased Composite Steel and Concrete Members (PEC members for short) consists of H-shaped cross-section of the main steel and concrete filling between the flange and the web, compared with the pure steel structure, the PEC structure has the advantages of high stiffness, high bearing capacity, good fire resistance and so on. The arrival of an earthquake may cause damage to building structures. The use of PEC structures can effectively improve their bearing capacity and seismic performance, and the method of post earthquake repair is relatively easier and more economical. In recent years, PEC components have been gradually popularized and applied in building structures.

Performance Evaluation and Mechanism Study of Solid Waste-Based Cementitious Materials for Solidifying Marine Soft Soil under Seawater Mixing and Erosion Action

The main purpose of this research is to develop a solid waste-based cementitious material (SWC) instead of cement for solidifying a large amount of marine soft soil with high water content and low bearing capacity in coastal areas. This aims to solve the problems encountered in the practical application of cement soil, such as slow strength growth and poor durability. The SWC includes ground granulated blast furnace slag (GGBS), dust ash (DA), and activated cinder powder (ACP), with admixtures of naphthalene sulfonate formaldehyde condensate (NS) and compound salt early strength agent (SA). Both the 7 d and 28 d compressive strength values of the SWC formulations G4 and G7 are about twice as strong as those of cement soil (GC), even when mixed with seawater. Immersion tests revealed that stabilized soil had superior resistance to seawater corrosion compared to cement soil. X-ray diffraction, scanning electron microscopy, infrared spectroscopy, and thermogravimetric analysis explained that the main hydration products in cement soil are C-S-H and CH, while in stabilized soil, SWC generates a large amount of C-A-S-H with gelling properties and AFt with filling properties. These hydration products have better effects on strength and seawater erosion resistance.

Use of threaded washers in the joints of wooden structures

Introduction. One of the promising types of joints in wooden structures is the joint using glued steel washers. However, the use of adhesive compounds is, for a number of reasons, characterized by lower manufacturability as compared to a threaded connection. Given the relevance of developing new technological types of joints in structures, it is necessary to study the threaded washer connection of wooden elements without the use of adhesives.Aim. To study the performance of a threaded washer connection by conducting a full-scale experiment of specimens exhibiting different parameters of threaded washers in order to assess the prospects for further study of the joint in question and its implementation in construction practice.Materials and methods. The procedure for studying the joint under consideration involves making a series of specimens and conducting an experiment to determine the failure loads and ultimate strains, followed by the visual inspection of these specimens after failure.Results. The experimental study of twelve specimens (four series of specimens exhibiting different parameters of threaded washers, with three specimens in each) yielded failure loads, and graphs showing their deformation were constructed. The performance of the joint in question was examined; its advantages and disadvantages in terms of bearing capacity, manufacturability, and reliability were identified.Conclusions. Threaded washer joints in wooden structures are characterized by high bearing capacity and manufacturability. In spite of such a disadvantage as the effect of wood moisture on the strength and reliability of this joint, its advantages make it promising for further study and use in construction practice.

Investigation on the pullout bearing properties and stress characteristics of fully grouted bolts in layered rock mass

AbstractCoal‐measure strata is a typical layered structure, a better understanding of the bearing characteristics of fully grouted bolts in layered rock mass is of great significance for roadway support. However, limited studies have been conducted to investigate the bearing performance of fully grouted bolts in layered rock mass. In this paper, a numerical model of fully grouted bolt in layered rock mass was established, and a tri‐linear bond–slip model of the anchorage interface was imported into the numerical model by the user‐defined Fish language. The effects of strata sequence, strata thickness, and strata number in layered rock mass on the bearing performance of fully grouted bolts were systematically analyzed. The results show that fully grouted bolts in soft–hard type (SH‐type) layered rock mass has higher bearing capacity. The greater the thickness of the soft rock in the layered rock mass, the more significant the influence of the strata sequence on the bearing performance of fully grouted bolts. The bearing capacity of fully grouted bolts decreases with the increase of the thickness ratio of soft rock to hard rock. The greater the thickness of the hard rock in the layered rock mass, the more beneficial to the bearing performance of fully grouted bolts. With the increase of the strata number, the bearing capacity of fully grouted bolts gradually decreases. For bolt support of layered rock mass, the deep anchoring foundation of fully grouted bolts should be arranged in hard rock or elastic zone rock as much as possible, and rock grouting can be adopted to reduce the difference in mechanical properties between layered rock mass and improve the durability of fully grouted bolts. The research results may provide useful guidance and reference for the support design of fully grouted bolts.

Experimental study on the composite reinforcement method for single-column piers in existing bridges

Steel–concrete composite reinforcement technology has developed rapidly in recent years. This method has emerged as one of the best reinforcement alternatives in bustling sections because it saves time and space. In this paper, a combination reinforcement plan for single-column piers in curved bridges is proposed, with its interface performance being comprehensively investigated. Nine sets of comparative experiments were conducted to analyze the key issue of shear resistance at the interface between new and old concrete in the combination reinforcement scheme. It was found that under the proposed circumferential reinforcement structure, the stress changed from interface shear to overall compression; therefore, both ductility and the failure bearing capacity were improved owing to the Poisson effect in the later stage of the interface treatment component. Meanwhile, using the calculation formulas in existing reinforcement specifications, we introduce the shear strength parameters under a new "serrated groove" situation, which has higher bearing capacity than the commonly used chiseling and groove modes. The methodology and findings of this study supplement the single-column pier combination reinforcement for existing bridges in urban sections and lays the foundation for future research.

Full-scale experiment on the bearing and deformation characteristics for prestressed double-layered shield tunnel linings under high internal pressure

To investigate the bearing mechanism for two types of circular anchorage prestressed double-layered shield tunnel lining under high internal pressure, a set of loading systems and measuring schemes were dedicatedly designed for the standing full-scale lining model. The results show that when the internal pressure reaches 1.10 MPa, the proportion of internal pressure transferred to the outer lining begins to increase with the expansion of the inner lining. When the internal pressure reaches 1.30 MPa, the local cracking of the inner lining will cause structural stiffness variation and stress redistribution, leading to a further increase in the proportion of internal pressure transferred to the outer lining. In addition, the detached bearing structure makes better use of prestress and has a higher bearing capacity, but lower engineering material economy than the combined bearing structure. For the combined bearing structure, there is an initial gap between the inner and outer lining at the left and right arch due to the prestress tensioning and concrete shrinkage. Moreover, it can give full play to the bearing performance of the segment and surrounding rock, thus optimizing the diameter of the prestressed steel strands. However, the initial gap has a certain influence on load-transferring, and it is necessary to control the concrete shrinkage and adopt the backfill grouting.

Improving Soft Subgrade Stability Using a Novel Sustainable Activated Binder Derived from By-Products

Soft soil concerns, due to high compressibility and low bearing capacity, prompted an investigation into stabilizing clay soil. Traditionally, binder including cement or lime has been used as stabilizers though a current requirement of alternatives is stem from environmental concerns. The study focused on the viability of using a novel binary activated blended binder composed of environmentally friendly materials, namely ground granulated blast furnace slag (GGBS) activated by cement kiln dust (CKD). The experimental work included investigating the impact of the developed binders on the Atterberg limits, standard Proctor compaction, California Bearing Ratio (CBR), unconfined compressive strength (UCS), and field-emission scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy. CBR tests were conducted after 7 days of curing or soaking, while UCS and SEM analyses were conducted after 7 and 28 days of curing. A fixed binder ratio of 9% was maintained, with GGBS blended at 25%, 50%, and 75% with CKD. For comparison, samples of untreated and treated soils with unary binders from GGBS and CKD were also prepared. Results indicated that activated binders notably decreased soil plasticity and maximum dry density, while elevating optimum moisture content, CBR, and UCS, especially in later stages of treated soil and unary GGBS binder. Unary CKD binder exhibited a similar trend to activated binders. The activating of 25% GGBS with 75% CKD provided the optimum binder which increased the mechanical strengths by about 6 times than untreated soil. SEM revealed substantial formations of C-S-H and C-A-H gel, along with ettringite, intensifying with time. This research provides viable outcomes for stabilizing clay soil using environmentally friendly binders, demonstrating significant improvements in soil properties, particularly when using the binary activated blended binder consisting of GGBS and CKD.Graphical

Stability analysis and design methods of steel pipe piles under non-uniform corrosion

Steel pipe piles (SPPs) are commonly applied for marine platform foundations due to high bearing capacity. However, for SPPs in corrosive marine environments, the corrosion on the steel tube is severe and shows a non-uniform distribution along the height direction, resulting in the significantdecrease of the stability bearing capacity. To investigate the stability performance of SPPs in marine corrosive environments, the corroded SPPs are simplified into five-segment stepped columns, and the equilibrium differential equations are established to obtain the rotational stiffness relationship. The analytical solutions of the critical buckling loads of five-segment stepped columns under arbitrary boundary conditions are obtained by iterative methods. Besides, considering the material and geometrical nonlinearity, the finite element (FE) model of corroded SPPs is established and then verified based on existing test results. The effects of the number of segments and stiffness ratios among different segments on the bearing capacity are analysed. Furthermore, considering the interactions among different segments, the calculation methods for the stability bearing capacity of stepped columns under axial compression and combined compression-bending are proposed respectively. The comparison between calculated and FE results indicates that the proposed calculation methods have good prediction accuracy and can be available for practical engineering reference.

Experimental analysis of RC and SPRC squat shear walls

Squat shear walls employed in nuclear power plants and high-rise buildings often undergo shear failure and exhibit poor ductility. The introduction of built-in steel plate improves the bearing capacity and ductility of shear walls. In this study, experiments were conducted to investigate the bearing and deformation capacity of squat steel plate reinforced concrete composite walls (SPRCW) and traditional reinforced concrete walls (RCW). Key parameters included the axial compression ratio, thickness of steel plates, and loading procedures. Specimens with axial compression ratio of 0.5 demonstrated high bearing capacity and poor ductility with sudden failure. Compared with RCWs, the bearing capacity of SPRCWs with 2 mm and 4 mm thickness steel plate was improved by 13 % and 40 %, respectively, whereas their ductility decreased by 29 % and 4 %, respectively, due to sudden welding failure. The bearing capacity of asymmetric-loaded specimens was slightly smaller than that of symmetric-loaded specimens, however, the ductility of asymmetric-loaded specimens was approximately 15 % greater than that of symmetric-loaded specimens, indicating that the overall damage to concrete significantly impacts ductility. Principal strains calculated from strain gauge rosettes revealed the failure path of SPRCW beginning in the interior of the wall and gradually expanding to the surface. Finally, calculation formulas for the bearing capacity of SPRCW were compared based on the experimental data. The values predicted by JGJ 138 were close to the experimental results, whereas AISC 341 was more conservative.

Gradient failure mechanism and control technology of deep roadways under the action of deviatoric stress field

Deformation control of deep roadways is a major challenge for mine safety production. Taking a deep roadway with a burial depth of 965 m in a mine in North China as the engineering background, on-site investigation found that significant creep deformation occurred in the surrounding rock of the roadway. The original supporting U-shaped steel support failed due to insufficient supporting strength. The rock mass near the roadway experienced a transition from triaxial stress conditions to biaxial and even uniaxial stress states as a result of excavation and unloading, leading to a gradient stress distribution in the surrounding rock. From the perspective of the roadway's deviatoric stress field distribution, we investigated the gradient failure mechanism of the roadway and validated it through theoretical analysis and numerical simulations. The study found that the ratio of horizontal principal stress and vertical principal stress determines the distribution shape of the surrounding rock deviatoric stress field. The gradient distribution of the stress field in the roadway will cause time-related deformation of the roadway, which will lead to large deformation and failure of the roadway. Based on this, the control mechanism of roadway gradient failure was studied, and then a combined support technology of CFST supports with high bearing capacity was proposed.

Innovative Methods to Improve the Seismic Performance of Precast Segmental and Hybrid Bridge Columns under Cyclic Loading

This paper investigates the seismic performance of prefabricated segmental bridge columns (PSBCs) with hybrid post-tensioned tendons and energy dissipation (ED) bars under cyclic loading. PSBCs with unbonded and hybrid bonded prestressed tendons and columns incorporating ED bars are designed to improve the lateral strength, energy dissipation, and limit the residual drift. The PSBCs under cyclic loading were investigated using the three-dimensional finite element (FE) modeling platform ABAQUS. The FE model was calibrated against experimental results, with an overall error of less than 10%. The seismic performance of the proposed PSBCs was evaluated based on critical parameters, including lateral strength, residual plastic displacement, and the energy dissipation capacity. The results show that bonding the tendons in the plastic hinge region as opposed to the overall bonding along the column leads to a better cyclic performance. The lateral strength, and recentering abilities are further improved by bonding tendons up to 2/3 of the length in the plastic hinge region, along with 100–300 mm in the footing. It was also found that selecting a longitudinal length of ED bars crossing multiple precast segmental joints and having a circumferential spread of 70–90% of core concrete results in a higher bearing capacity and energy dissipation compared to ED bars crossing the single joint.

Research on bearing capacity and stability of deep-water novel combined wellhead based on experimental methods

The combined wellhead has the advantage of high bearing capacity and broad prospects for application in the construction of deep water surface wells; therefore, it is important to conduct relevant research to guide the construction of combined wellheads. The aim of this paper is to study the mechanical characteristics of the combined wellhead in the longitudinal direction and establish the method for real-time calculation of the bearing capacity of the combined wellhead taking into account the effects of installation. The variations of external wall pressure and internal soil pressure during installation and the waiting process of the combined wellhead were investigated by indoor experiments. The installation efficiency of the combined wellhead at different negative pressure conditions was also compared. The experimental results show that the pressure on the outer wall of the combined wellhead facility gradually increases as the depth of the combined wellhead facility increases, and the closer it is to the bottom, the greater the soil pressure. The pressure on the inner soil will increase rapidly during the installation process to almost the same level, while the pressure on the outer soil will increase slightly. During the waiting process of the combined wellhead, as the waiting time increases, the soil damaged during the installation process gradually recovers, and the external wall pressure gradually rises. Moreover, the pressure on the outer wall gradually increases, the pressure on the inner soil decreases slightly leveling off within about 24 h. An appropriate increase in suction pressure facilitates the installation of the combined wellhead, and approximately 2.0 L/min is the optimal option for installation. The computational model developed in this paper and the experimental measurements corroborate each other. These combined wellheads significantly improve the stability of deep water soft-soil well construction and provide a theoretical benchmark for developing oil, gas and hydration in deep water.