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In urban areas with scarce land resources, many deep excavations are performed adjacent to flexible retaining walls. This study investigated the influence of a flexible retaining wall on the performance of an adjacent deep excavation through numerical modeling. The numerical method incorporating the hardening soil small-strain model and input parameters were primarily validated using a well-documented case. Hypothetical models with different spacings between the deep excavation and existing flexible retaining wall were established to study the deformation behavior of diaphragm walls and characteristics of lateral earth pressure. Parametric studies were carried out to investigated the influence of the excavation width, wall depth, and bending rigidity of retaining walls on the performance of the excavation. Finally, the mechanisms of the flexible retaining wall to influence the mobilization of the arching effect in confined soil were discussed. Results show that the adjacent flexible retaining wall aggravates maximum wall deformation and leads to the inclination of the excavation. The impact is mainly attributed to the redistribution of lateral earth pressure resulted from the mobilization of the arching effect. However, the influence of the flexible retaining wall on the magnitude of the resultant force of lateral earth pressure is insignificant. Both qualitative analysis and numerical results prove that the general shape of the major principal stress trace is a curve convex to stabilized soil when the arching effect is generated.

Deformations in deep excavations can be controlled by providing adjustable support using servo struts; however, the design of strut positions and applied forces remains to be optimized. In this study, the influences of varied forces applied by servo struts on excavation-induced wall deflection and ground settlement were analyzed through numerical simulations and a field investigation. A reference numerical model and input parameters were validated using a well-documented excavation case study. Using the validated model, three servo struts were installed on a diaphragm wall at the top, middle, and bottom levels of an excavation model, and a constant force was applied on the beam elements. Comprehensive numerical simulations were carried out with various forces applied at the upper-, middle-, and lower-level struts. Both wall deflection and ground settlement were analyzed in relation to the applied force. Additionally, a field investigation was carried out at an excavation site in Hangzhou, China, where comparative analyses of applied forces and servo strut locations were performed. Both the numerical and field results confirm the effectiveness of servo struts in controlling excavation-induced wall deflection and ground surface settlement. Their effectiveness is closely related to their applied force and installation position. Wall deformation and ground settlement decrease with increases in applied force. Middle-level servo struts showed the greatest efficiency in controlling maximum wall displacement and maximum ground surface settlement.

With the large-scale development and utilization of ocean resources and space, it is inevitable to encounter existing submarine facilities in pile driving areas, which necessitates a safety assessm...

Existing solutions for axisymmetric active earth pressure are based on certain hypotheses of the circumferential stress, lacking of strict basis. This article presents a technique for deriving the actual circumferential stress according to the circumferential geometric condition, the Drucker-Prager criterion and incremental theory. Based on the actual circumferential stress, a new characteristics method for determining the axisymmetric active earth pressure in plastic flow is developed in this article. In this new method, the inclined angle of boundaries, interface friction of contact interface, dilatation effect and flow velocity of soil are considered at the same time. The validity of the new method is confirmed using several sets of experimental data from the literature. The pressure coefficients are investigated individually in detail, and some different conclusions are found. Finally, a practical formula for calculating axisymmetric active earth pressure is presented based on the linear superposition principle, and related tables of coefficients are also provided for engineering application.

Offshore installations with pile foundations in shallow water are vulnerable to submarine landslides, which cause serious damage to engineering facilities, loss of life, and loss of money. Due to a shortage of real observation data and the difficulty of reproduction, we lack insight into the interaction behavior between submarine landslides and monopiles. This study capitalized on ANSYS Fluent 20.0 to develop a three-dimensional biphasic (water and slurry) numerical model. This CFD model was used to analyze the interaction between a monopile and submarine landslides at different flow heights. The velocities of submarine landslides were from low to high values. Two modes of interactional forces acting on the monopile are proposed, which are (i) interaction force with peak value and (ii) interaction force without peak value. The influence of flow height and velocity on interaction forces was investigated. Results show that the effect of the flow heights on the interaction force is significant at low velocity stage, while the peak force representing a hazard level of the pile was non-negligible under high flow velocity and low flow height conditions, which should be considered in a future study. The related mechanisms are revealed with a hybrid model considering different components of the force.

This paper proposes an improved soil-water-structure coupled interaction model within the framework of smoothed particle hydrodynamics (SPH). The continuous penetration process of the spudcan in clayey soil was investigated along with the concomitant variation of pore water pressure. The proposed method enables the efficient capturing of excess pore water pressure variation in soil undergoing large deformations. Verification and validation performed using previous numerical investigations and centrifuge test data indicate that the proposed model is valid, robust, and effective. This model can be employed to solve various penetration problems and other problems involving complex soil-water-structure interaction and large soil deformations.

Responses of a substructure adjacent to deep excavations are complex, especially when the substructure is connected to the supporting systems of the excavations. In this study, a three-dimensional (3D) numerical model is developed by finite difference (FD) software, FLAC3D v5.0, to examine the responses of a metro line to deep excavations through a case history in Shanghai, China. The developed numerical model includes four deep excavations, which were located at two sides of the metro line and were connected to the structures of the metro station. These deep excavations were constructed in stages and the construction processes are simulated in accordance with the practical execution. Responses of the rails to the deep excavations are illustrated and the numerical results are compared to the measured data to validate the developed numerical model and input parameters. Moreover, 3D structural responses of the metro station and shield tunnels to the deep excavations are presented and analyzed. Numerical results indicate that (i) the walls of the station move upward during the excavations and the slabs are uplifted by the walls; (ii) The station heaves significantly whereas the shield tunnels settle slightly. (iii) The station will be distorted if the unloading is asymmetric.

This study proposed and applied a three-dimensional (3-D) numerical model based on existing 1-D and 2-D numerical models to investigate residual soil response in a homogeneous sandy seabed with a rocking mono-pile subjected to a cyclic lateral load and waves. The wave motion is governed by the Reynolds-averaged Navier-Stokes (RANS) equations. Compared to previous studies in the literature, this research analyzed the pore pressure accumulation due to wave-pile-seabed interaction considering the pile rocking effect. The proposed 3-D model is validated against existing experimental and numerical data. Subsequently, the 3-D model is used to investigate the residual response of a seabed with a mono-pile, in which pile rocking caused by a lateral cyclic load is considered. The results indicate that the existence of a rocking mono-pile greatly affects the residual response of the seabed due to pile-seabed interaction. The rate of residual pore pressure buildup was significantly faster near the mono-pile surface due to the impermeable interface and stiffness difference of the pile and seabed soil. In addition, the effect of pile rocking leads to the variation in shear stress in various parts of the seabed, resulting in different residual pore pressure variations at various positions around the mono-pile.

A novel algorithm was developed based on the two-phase mixture theory within the framework of Smoothed Particle Hydrodynamics (SPH) aiming at simulating the complex soil-water-structure interaction when soil undergoes large deformation. In the algorithm, each constitute is assumed to occupy a certain part of the macroscopic mixture and satisfies its own conservation equations. The soil-water interaction force was composed of pore water pressure and viscous drag force. The spudcan was assumed to be rigid. Frictional sliding contact was employed to modify the momentum equation for particles located near or on the structure surface. With the proposed algorithm, it can investigate the pore water pressure, the effective stress and the porosity for soil undergoing extremely large deformation. Afterwards, its application to the simulation of continuous penetration of the spudcan was presented. The calculated pore water pressure and penetration resistance were compared to the previous research, indicating promising robustness and applicability of the present algorithm. Furthermore, the proposed algorithm could be a potentially efficient tool helping to solve other problems involving soil large deformation and complex soil-water-structure interaction such as deep penetration, underwater excavation, piping and so on, which is quite difficult dealing with traditional mesh-based methods.

Blast response of submerged pipelines has been a research focus in recent years. In this article, a three-dimensional numerical model is established to investigate dynamic response of pipelines due...

This research presents a holistic approach to the protection of historical building group adjacent to metro line construction, in which health investigation, protection criterion determining, numerical simulation analyses, corresponding protection measures and field monitoring analyses are incorporated as main procedures. A case relating to the conservation of a seven-storey brick-wood pagoda, Longhua Pagoda, adjacent to the construction of Shanghai Metro Lines 11 and 12 in China, is presented. A reasonable protection criterion is determined rationally by means of numerical simulation based on the health investigation results combined with related standards, which can help to achieve a fine balance between system safety and cost constraints in protection measures determining. A full numerical model is developed to analyze the effect of dewatering, excavation, tunneling, and shield departure/reception, and corresponding measures are adopted to ensure the safety of the pagoda. Especially a brand new method, steel jacket method, is introduced in detail, which has a good performance on decreasing the amount of dewatering and maintaining a stable working face. Results demonstrate the application potential of the proposed approach, as well as its feasibility. The proposed approach can be used in the industry by practitioners to provide positive guidelines on the conservation of historical building group against metro line constructions. The reliable and detailed data in this case can also provide verification for subsequent research.

When several adjacent foundation pits are excavated simultaneously and alternately, the foundation pit group has the interactions which will aggravate the excavation-induced adverse impact on surrounding environment. However, due to the massive construction information and monitoring data during excavation, the effect of interactions on performance of the foundation pits is hardly examined. In this study, a digital system is developed to manage the construction information and monitoring data of the foundation pit group. On the one hand, a visualization management system based on Autodesk Revit is developed to record information such as geometry information, excavation stages, and instrument layout. The complex construction information can be inquired dynamically. On the other hand, a dynamic and synchronous analysis system is developed based on SQL Server external database, Visio, and Excel software. The SQL Server software is capable to facilitate data classification and standardization management. The excavation process and monitoring data are fused through the secondary development of Visio and Excel software to help visualize, respectively. The developed system is applied to the foundation pit group of Shanghai World Expo Project. The lateral deflection of diaphragm walls is investigated and the rebound phenomenon of diaphragm wall is interpreted. It confirms that the developed system can improve the information management so that the deformation behavior of the foundation pit group can be analyzed efficiently.

Rankine pressure involves the special case of active earth pressure and merely considers the influence of the internal friction angle; however, the analytical solution for the general case...

To address the effects of well and aquifer clogging and variable injection rate on groundwater flow dynamics, an analytical model of well hydraulics is developed for the artificial recharge using a fully penetrating well. In this model, the clogging-related hydraulic conductivity of the recharged aquifer is assumed to decay exponentially with time. Meanwhile, the injection rate is considered as a sinusoidal function over time. An analytical solution is obtained by solving the model using the Hankel transform. Then, a parametric study is conducted to investigate the effect of sinusoidal-rate injection and exponentially decayed permeability on groundwater flow dynamics. The results indicate that (1) the inhibition and hysteresis in hydraulic conductivity causes the discrepancy in the distribution of hydraulic head increment (s) between the variable- and constant-rate injections. (2) The discrepancy in the distribution of s is more obvious under the injection rate with smaller frequency and larger amplitude. (3) The permeability reduction increases the hydraulic conductivity hysteresis and the discrepancies in s between the variable- and constant-rate injections. (4) The larger permeability reduction causes higher injection pressure at the wellbore and induces a larger s around the injection well but smaller one in far-field. Furthermore, a method using optimized back-propagation artificial neural network based on genetic algorithm is successively developed for aquifer parameter estimation. The findings of this study offer the better sight on the groundwater flow dynamics in confined aquifers under the combined effects of clogging-induced permeability reduction and variable-rate injection.

Real dynamic compaction (DC) sites are composed of a series of tamping locations. However, previous studies mainly focused on single-location tamping and paid little attention to the influe...

Existing axisymmetric slip-line theories for metal are established based on certain hypotheses of circumferential stress and thus lack strictness. This article presents a technique for deri...

Pile rocking is the motion of a mono-pile foundation as a result of cyclic loads caused by wind and wave, and the effect of upper structures such as offshore wind turbines. The rocking effect further complicates the interaction between a mono-pile and the seabed and results in instability of offshore structures. In this research, a three-dimensional integrated numerical model, combining the effect of wave loads with the seabed and mono-pile, is adopted to investigate wave-structure-seabed interaction (WSSI) considering the pile rocking effect. The present model is validated by available laboratory experiment data and analytical results. In addition, a detailed comparison with a non-rocking single pile is conducted to examine the effect of pile rocking on soil response more clearly. Finally, the momentary liquefaction depth is investigated and a parametric study on pore pressure response has been carried out. Results indicate that local pressure enlargement occurs near the mudline and the rate of pore pressure decrease in depth is slowed down due to pile rocking, leading to a relatively high pore pressure in the upper soil range. Furthermore, the pile rocking effect has a significant influence on the liquefaction distribution and enlarges the liquefaction zone in the vicinity of mono-pile foundation.

Although an appropriate construction method contributes to minimizing the excavation-induced impact on existing facilities, few studies have focused on the comparison and optimization of the construction methods for engineering projects in practice. In this paper, Three-dimensional (3D) numerical simulations are carried out to compare the construction methods for an excavation above shield tunnels through a case history, which has been constructed by a novel excavation method, referred to as divided alternate excavation method (DAEM). A 3D numerical model is developed in the finite element (FE) software, ABAQUS 6.10, to simulate the practical construction process of the DAEM, and the numerical results are analyzed in combination with the field data. Comparative studies are performed by simulating the hypothetical construction schemes of two conventional excavation methods that were proposed for the investigated case. Numerical results confirm the effectiveness of the DAEM on controlling the excavation-induced underlying tunnel deformation. Extensive parametric studies of the DAEM are performed for further investigation. Through the comparative studies and parametric studies, suggestions are proposed for optimization of construction methods for deep excavations above shield tunnels.

Research on the response of random wave on offshore structures has received great deal of attention of many researchers and engineers in the design of marine structures. Most previous investigations have been limited to the regular waves. In this paper, based on Longuet–Higgins random wave theory and finite element method, a numerical model for random wave-induced seabed response is established. The seabed is treated as poroelastic medium and characterized by Biot’s partly dynamic equations (u–p model). The JONSWAP spectrum is adopted in Longuet–Higgins model, which is based on the cumulative superposition of linear diffraction solution. Based on the numerical results, the effects of random wave on seabed response are investigated by comparing with the corresponding Stokes wave and cnoidal wave. Then, a parametric study is conducted to examine the effect of wave and soil characteristic on the seabed.

The execution of deep excavation above confined aquifers asks for dewatering measurements to reduce the hydrostatic pressure so that the safety of the deep excavation can be assured. Dewatering will inevitably cause deformations in the surrounding strata. To reduce the dewatering-induced strata movement, an innovative pumping-recharge technology has been developed in which the dewatering is carried out in the excavation and the recharge is conducted near the protected facilities. However, the capacity and efficiency of this technology in deep confined aquifers need to be further investigated. This paper presents two in-situ pumping-recharge tests in a deep confined aquifer under a deep foundation pit. The feasibility of artificial recharge in the deep confined aquifer has been verified by conducting a single-well pumping and multi-well recharge test with different discharge and injection rates. Then a multi-well pumping-recharge test was carried out in accordance with the requirement and circumstance of construction to evaluate the capacity and efficiency of recharge in controlling the drawdown and ground settlement. The results showed that multi-well recharge could form a water curtain which has a water-proof function to reduce the groundwater drawdown. Meanwhile, by controlling the groundwater head of the confined aquifer during the recharge, the pumping-induced settlement of the surrounding area can be reduced or even eliminated. The pumping effect in the pit would be affected by the recharge around the protected facilities, so it is necessary to take in-situ pumping-recharge tests to determine the layout of wells and the discharge and injection rate. Finally, the artificial recharge was applied to the construction of a deep excavation in Shanghai, and the drawdown and the ground settlement around the protected buildings were effectively controlled by recharge.

Construction of an underground complex in congested urban areas calls for excavation of a group of foundation pits, referred to as a pit complex, which are usually surrounded by existing facilities. In such circumstances, the safety of the pit complex and facilities during the construction are of great concern. This paper presents a case of an underground complex construction in Shanghai soft clay. A pit complex composed of two deep excavations was excavated for a Comprehensive Transport Hub (CTH) and a commercial retail area and pedestrian concourse known as South Square (SS), which were connected to an operating metro station and a railway station. During the excavation, potential deformation of metro tracks and railway tracks were expected due to extensive soil unloading. To safeguard the railway and the subway, a zoned and staged construction technology was proposed, in which several temporary partition walls were constructed in addition to necessary supporting structures, to allow the large-scale deep excavations to be divided into several independent small-scale excavations. This paper discusses the rational construction sequence of these excavations as well as reinforcement measures in detail. The construction technology was examined by extensive field data. It is found that the maximum horizontal displacement of diaphragm walls ranged between 0.05% H e and 0.4% H e , where H e is the excavation depth. The vertical displacements of the railway tracks were well controlled, whereas the metro tracks heaved significantly due to unloading effect.

In saturated fine-grained soil, the development and dissipation of excess pore water pressure (EPWP) during and after pile jacking change the effective stress of the surrounding soil, and thereby affect the pile set-up. In this paper, the entire process of steel-pipe pile jacking (the installation process and the subsequent consolidation phase) is simulated with three-dimensional (3D) finite element models, considering the pore water effect. After the model verification, a comprehensive numerical analysis was performed to investigate the development and dissipation of EPWP, changes in soil stress state, and the side shear resistance of pile with time after installation. On this basis, not only the influence of ks, cu, E, and OCR on EPWP generation during pile jacking and subsequent soil consolidation effect after pile installation but also the correlation between pile set-up and EPWP dissipation is investigated.

Land subsidence is a severe geo-hazard in coastal regions and represents a great threat to infrastructure. Based on long-term measurement data, including that for deep compaction from vertical multipoint extensometers, land subsidence and infrastructural settlement from leveling surveys, groundwater levels in multiple confined aquifers, and hydrogeological conditions, this study investigates the effects of groundwater exploitation and recharge on land subsidence and the settlement of infrastructure in Shanghai, China. Further, groundwater exploitation and the consequent responses of piezometric heads in the multiple confined aquifers of Shanghai soft deposits are discussed. Subsequently, regional land subsidence, local deep-soil deformation, and infrastructural settlement are analyzed in terms of groundwater exploitation. It is found that the subsidence pattern is related to the trend of groundwater exploitation and the variation of piezometric heads in the aquifers, which can be roughly divided into three phases. Subsidence funnels could occur, and could be interpreted according to the differences in groundwater exploitation intensity and the spatial variability of lithology. Since the towers of Nanpu Bridge are located within the area of the subsidence funnel, this could be the main reason for the differential settlement of the bridge.

Dynamic compaction (DC) is an efficient soil improvement technique. The previous numerical studies mainly focus on the soil response of single location tamping, but ignore the soil compaction degree under multilocation tamping. In this study, a numerical investigation of multi-location tamping in granular soils is carried out using three-dimensional (3D) finite element model (FEM). The behaviors of the granular soils are described by means of the viscoplastic cap model. The constitutive relationship of the soils is implemented into LS-DYNA and is integrated with 3D FEM for numerical investigation. Then utilizing the field data from the previous studies, we investigate the soil compaction degree at different stages by a case of two basic patterns, and discuss the cause of soil response. Lastly, we evaluate the effect of construction parameters on soil compaction. The simulation results show that the previous tamping affects the soil compaction degree beneath the adjacent tamping location, and the effect is greater near the side of previous location. Meanwhile, the soil compaction degree around the existing tamping crater weakens due to the adjacent tamping. Moreover, the rational selection of DC construction parameters can improve the soil compaction degree, and some hints on the effect of soil compaction are given.

Load conditions for steel pipe-jacking are complex during the construction stage. The stability of steel jacking pipe has been an increasingly important problem as jacking forces, pipe diameters and jacking distances increase. However, there are no standards for pipe reinforcement, for prevention of buckling, or for remedying pipe that buckles when being jacked axially. Past experience suggests that stiffeners can effectively reinforce the structure. This study analyzes the effect of different stiffeners on the stability of steel jacking pipe under axial compression using finite element analysis. The results suggest that the stability of steel jacking pipe can be significantly improved by using orthogonal stiffeners, in terms of engineering costs and construction space inside the pipe. Based on current engineering practice, the application of orthogonal stiffeners is discussed. This study provides a useful reference for the design and construction of steel jacking pipe.

Groundwater drawdown and strata settlements induced by dewatering in confined aquifers can be relieved by artificial recharge. In this study, numerical simulations of a field multi-well pumping-recharge test in a deep confined aquifer are conducted to analyze the responses of groundwater and strata to pumping and recharge. A three-dimensional numerical model is developed in a finite-difference software, which considers the fluid-mechanical interaction using the Biot consolidation theory. The predicted groundwater drawdown and ground settlements are compared to the measured data to confirm the validation of the numerical analysis of the pumping and recharge. Both numerical results and measured data indicate that the effect of recharge on controlling the groundwater drawdown and strata settlements correlates with the injection rate and well arrangements. Since the groundwater drawdown induced by pumping can be controlled by artificial recharge, soil compression can be relieved by reducing the changes of effective stress of the soils. Consequently, strata settlement induced by pumping can be relieved by artificial recharge and ground settlements can be eliminated if an appropriate injection rate and well arrangement are being determined. Moreover, the changes of the pore pressure and seepage force induced by pumping and recharge will also result in significant horizontal deformations in the strata near the recharge wells.

The pressure on a tunnel lining is an important issue in shield tunnel design, because it is related to the safety and durability of the lining. There is an increasing need for short (about 1 km) but wide traffic tunnels in parts of China near rivers. In order to satisfy the gradient requirement of the road over such a short distance, the depth of the overburden is inevitably very shallow. The non-uniform distribution of the pressure on the lining of this kind of tunnel may result in damage to the tunnel segments. However, little published research is available on this topic. In this study, in-situ monitoring was carried out to measure the pressure on the lining of a large cross-river shield tunnel (diameter D = 11.36 m) with a shallow overburden (0.7 D) in silty-sandy ground. A pad type earth pressure gauges and pore-water pressure gauges were used to measure the pressures on the tunnel lining, including the tail brush pressure, grouting pressure, earth pressure and pore-water pressure. The time history and the distribution of pressures on the lining during tunnel construction and post-construction were obtained. A comparison between the measured values and theoretical values was carried out. This showed that the tail brush pressure had a considerable effect on the segments while the shield machine was passing through. Non-uniform tail brush pressures caused cracking and water leakage in the concrete segments. The maximum pressure induced by the backfill grouting was twice that of the theoretical earth pressure. However, the non-uniformity of the backfill grouting induced pressure was not as great as that induced by the tail brushes. In the silty-sandy ground, the earth pressures were generally stable 24 h after segment assembly. The final stable values were close to the total overburden pressure, particularly at the tunnel crown. The pore-water pressure generally was equal to the hydrostatic pressure and accounts for a large proportion of the total earth pressure.

In practice, the steel pipe-jacking can be regarded as a thin-walled cylindrical shell mainly subjected to jacking force in the axial direction and surrounded by the soil which is usually simplified and modeled as an elastic foundation. In this paper, the elastic buckling behavior of steel jacking pipes primarily under axial compression and with the Pasternak foundation is analyzed by the finite strip method (FSM). The elastic foundation is considered in the stiffness matrix through the strain energy, and the deformation in the longitudinal direction is simulated by the series functions in FSM. A parametric study is conducted to analyze buckling of cylindrical shells embedded in different elastic foundations. It indicates that the Pasternak foundation is more conducive to prevent buckling of cylindrical shells under axial compression. The critical length and the lower bound of buckling loads are obtained, and they offer the basis for optimal design of steel pipe-jacking. Finally, the case study combined with the buckling accident in the steel pipe-jacking event is presented. The present buckling analysis of soil-embedded cylindrical shells under axial compression provides design guidance for steel pipe-jacking construction.

A numerical investigation into the performance of ground deformation due to dynamic compaction (DC), and a developed method of estimating ground deformation of granular soils caused by DC are presented. Firstly, a 2D numerical model is created in LS-DYNA and the result is verified by variables measured in a real field case using DC treatment. A simplified model for describing ground deformation is presented. Five deformation variables, δ v m , d δ v =0 , d δ u m , δ u m , d δ u =0.01% W t H , are defined to describe characteristics of ground surface deformation. An extensive parametric study is then conducted to investigate the effect of each parameter on the five deformation variables. Finally, based on the results obtained, a forecast model is produced to describe ground deformation under DC. The applicability of the proposed procedure is then illustrated by comparing its predictions with a case of DC applied in the field. The results of this comparison indicate that the predictions using the developed method are reasonably realistic. This suggested method can provide some easy and convenient guidelines to determine ground deformation of granular soils due to dynamic compaction.

In this, the second part of two companion papers, three-dimensional finite-element modelling of the shear load tests is presented and the shear bearing behaviour of the cross-plate joints is predicted. The isotropic damage plasticity model is adopted to model the non-linear behaviour of concrete and the interface, and the quasi-static load test process is approximately simulated with an explicit technique employing an artificial timestep to decrease the kinetic energy. The numerical analysis method is verified using the experimental results presented in the first part of the two companion papers, and the shear behaviour and shear bearing capacity of the cross-plate joints are evaluated numerically. The numerical results and parametric study reveal the load-bearing mechanism and failure modes of the joints. By introducing a correction coefficient considering the effect of the hole ratio in the longitudinal plate and based on the analytical expression for the ultimate shear load of perfobond connectors, a new and modified prediction formula for the shear bearing capacity of cross-plate joints is proposed. The close correlation of the prediction formula with the numerical and experimental results demonstrates that the proposed formula is reliable for predicting the ultimate shear load of cross-plate joints.

This paper, the first part of two companion papers, describes a test programme involving seven specimens and experiments to investigate the effect of three main design parameters of longitudinal steel plates in cross-plate joints on the shear capacity. The load–displacement relationship, cracking of the concrete and strain of the longitudinal steel plate were experimentally measured. It was found that the failure modes of the specimens can be categorised into two types – concrete crushing and steel plate yielding. The failure mode is mainly affected by the relative stiffness of the cross-plate joints, while the ultimate shear load is primarily influenced by the number and area ratio of holes in the longitudinal plates. The paper shows that the available analytical expression for the shear capacity of rib shear connectors cannot be readily applied to cross-plate joints, and therefore further investigations should be conducted to develop a new shear capacity prediction formula for cross-plate joints. This experimental study on the performance of concrete diaphragm walls with cross-plate joints sheds light on the shear failure behaviour of diagram walls and provides some benchmark data for numerical analysis and development of empirical design formulae.