Middle Of Wall Research Articles

Explicit Dynamic Analysis by a Rigid Body-Spring Model of Impact Loads of Artillery on Middle Age Fortifications

The development of artillery in Europe at the end of the Middle Ages brought a necessary change in military architecture. This change was a radical rethinking of the entire geometry and architectural design of city walls which required an increase in thickness to resist repeated artillery strikes. The damage due to the impact loads on Middle Age fortification walls is analyzed herein with explicit dynamic analyses. This study was developed both with finite element models and an innovative rigid body-spring model with diagonal springs (RBSM), showing the different peculiarities of these two different approaches and how their results can be integrated. The numerical models clearly showed that the presence of an inner core of softer material tends to modify the impact effects by reducing the degree of damage at the expense of an extension of the damaged area.

Seismic performance of a new type of precast shear walls with non-connected vertical distributed reinforcement

To eliminate the shortcomings in the grouting sleeve and other connection forms in precast concrete shear wall structure induced by the poor grouting, difficult quality assurance, low construction efficiency, and high cost, a new type of monolithic assembled concrete shear wall structure with non-connected vertical distributed reinforcement was proposed in this paper. The new shear wall structure is composed of middle precast wall panels and cast-in-place boundary members. The vertical distributed reinforcement in the middle precast wall panels is not connected between the upper and lower floors. This technique was based on the normal section bearing capacity of equal strength and inclined section bearing capacity of equal strength compared with the cast-in-place shear wall structure. Three full-scale models of precast shear walls and one cast-in-place contrast specimen were tested for their seismic performance under pseudo-static loading. All precast specimens are cast based on the manufacture specification of the factory. By analysis of test results, including the failure modes, load-lateral drift hysteresis curves, bearing capacity, hysteretic characteristics, deformation components, ductility, rigidity degeneration, energy dissipation, and strain distribution, all the specimens were obtained and compared. Comparisons between test results indicate that the proposed shear walls have a similar bearing capacity as that of the cast-in-place shear wall and improved energy dissipation and ductility. Moreover, the specimen with inclined reinforcement performs better in drift capacity compared to companion specimens. The contribution of flexural deformation to the total displacement of each specimen is the largest, follow by the contribution of shear deformation, and the contribution of slip is the smallest. The strain of non-connected vertical distributed reinforcement of the precast panel did not yield during the loading process. The cross-section of the precast shear wall panel conforms to the assumption of plane cross-section according to the strain distribution before the reinforcement yields.

When COVID-19 delays the management of an urgent heart condition: A rare case of a spontaneous dissection of two coronary arteries.

Some severe life‐threatening conditions could be misdiagnosed during the current COVID‐19 pandemic.

Utility of quantitative magnetic resonance angiography and non-invasive optimal vessel analysis for identification of complications and long-term hemodynamic changes in post-pipeline embolization patients.

Quantitative magnetic resonance angiography and non-invasive optimal vessel analysis serve as powerful tools to collect and analyze hemodynamic data from pipeline embolization patients. At our institution, patients receive post-embolization quantitative magnetic resonance angiography within 24 h of treatment and within 6 months for follow-up to evaluate pipeline patency. Here, we aim to elucidate the long-term hemodynamic changes following pipeline embolization device placement and report two cases in which in-stent stenosis was detected. Medical records of patients who underwent pipeline embolization device placement for an internal carotid artery aneurysm between 2017 and 2019 were reviewed. Patients who received post-procedure NOVA and follow-up NOVA were included in the study (n = 32). Location and size of aneurysm, number of pipeline embolization device deployed, and complications were collected along with the non-invasive optimal vessel analysis report (flow volume rate (ml/min), mean, systolic, and diastolic flow velocities (cm/s), and vessel diameter (mm)). Internal carotid artery vessel flow rate was measured proximal to the pipeline embolization device. Derivations of hemodynamic parameters (pulsatility index, Lindegaard ratio, and wall shear stress) were calculated. The middle cerebral artery mean and diastolic flow velocities were significantly lower on the follow-up NOVA compared to the post-procedure NOVA. Moreover, follow-up NOVA demonstrated lower middle cerebral artery wall shear stress on the side with flow diversion compared to the post-procedure NOVA. In-stent stenosis, requiring intervention, was detected in two patients on follow-up NOVA. One patient had a successful balloon angioplasty of the stented internal carotid artery that resolved her stenosis. However, the second patient developed progressive stenosis and expired despite intervention. Long-term hemodynamic adaptations post-pipeline embolization device demonstrate decreased wall shear stress and decreased mean and diastolic flow velocities in the distal middle cerebral artery, which suggest decreasing velocity of blood flow with endothelialization of the device. Furthermore, follow-up NOVA is a useful tool for detecting potential flow-related complications such as in-stent stenosis.

Pattern of cholesteatomas under a scanning electron microscope - a risk factor for bone resorption.

SUMMARYObjectiveThe damaging effect of cholesteatomas presents mainly as bone resorption by osteoclasts located in the space between the bone and perimatrix. This process is initiated by the molecular cascade of osteoclast differentiation factors. The aim of the study is to analyse cholesteatoma microstructures via scanning electron microscope (SEM), and associate them with risk and grade of bone erosion.MethodsPathological middle ear tissue fragments with cholesteatoma visible under a microscope were collected from 58 patients operated on for chronic otitis media with features of bone defects in the middle ear walls. These fragments were examined under a scanning electron microscope.ResultsAnalysis of the cholesteatomas’ surface under a SEM revealed both regular and irregular structure of the matrix, most being the latter. Irregular matrix structures were observed in cases with a short disease history and in patients for whom this was the first surgical procedure. In our analysis, a cholesteatoma matrix with regular structures was associated with less bone destruction of the middle ear space.ConclusionsThe microstructure of cholesteatomas that showed regular layers under SEM coincides with reduced destruction of the middle ear bone walls. An irregular structure (pathognomonic for a process with a short medical history, and in patients operated on for the first time) is characterised by a tendency towards deeper destruction of bone tissue.

Effects of Particle Properties on Visualizing Flows in a Two- Stage Electrostatic Precipitator Using Particle Image Velocimetry

The amount of particulate matter (PM) in the environment has been confirmed to be health risks on human bodies[1, 2], and therefore removing suspended particles has become the research goal of many studies. Electrostatic precipitator (ESP) is one of the high-efficiency particle collection technologies[3-7]. Particle Image Velocimetry (PIV) has been an effective tool for visualizing the flow patterns in experimental fluid mechanics, and many studies adopted this technique to study flows in ESP[8-10]. However, particles charged by the electric field can cause deviation in measurement results since it does not follow the ionized air flow which can be charged differently from the tracer particles. In this study, the observation of the effects of different particle properties on flow field in a two-stage ESP is the objectives of this study. A two-stage ESP was built and four different seeding particles, aluminum oxide (Al2O3) particle, oil droplet particle, sodium chloride (NaCl) particle, and titanium dioxide (TiO2) particle, are tested in the current study. In this study, the streamwise velocity of the flows ranges from 2.36 m/s to 4.18 m/s, the voltage of the corona electrode varies from 8 kV to 12 kV with a positive polarity, and the voltage of the collector electrode is fixed at 16 kV. To investigate the 3-D flow patterns inside the channel, data at different planes were taken for comparison. The results show that by increasing charge voltage from 8 kV to 12 kV with a streamwise flow velocity the 2.36 m/s, the y-component velocity for Al2O3 particle, oil droplet particle, NaCl particle and TiO2 particle increased by 50.6%, 76.0%, 33.5% and 51.9%, respectively. Moreover, for the case of the 4.18 m/s primary flow, the y-component velocity for Al2O3 particle, oil droplet particle, NaCl particle and TiO2 particle increase by 52.7%, 59.2%, 59.4% and 65.9% after the voltages increase from 8 kV to 12 kV. PIV results for oil droplet particle shows slower y-component velocities, which can be due to the lower Archimedes number of 3.12E-06 and the mobility number that is larger than 3. On the contrary, in most of results from TiO2 particles show high y-component velocity, which is due to the highest Archimedes number of 1.15E-03 of the seeding particles tested in this study. This result shows that the particle is less affected by buoyancy effect. The PIV results of the middle plane also shows that the ycomponent of velocity from -2.6 m/s to -0.5 m/s, in contrast to -1.0 m/s to 1.0 m/s from the near wall observation plane. These results are consistent to simulation results of the electric field distribution, whichshows unequal electric field strengths between the middle and near wall regions of the test section. Only half of the cage shape distribution of the electric field can be observed, and primary flow influences the ionic wind to move to the downstream area. Based on the results, the oil droplet and TiO2 particles are more suitable for the role of tracer particles compared to aluminum oxide and sodium chloride particles.

B-PO04-173 RING-LIKE LATE GADOLINIUM ENHANCEMENT FOR PREDICTING VENTRICULAR TACHYARRHYTHMIAS IN DILATED CARDIOMYOPATHY

Myocardial fibrosis has been correlated with clinical ventricular tachyarrhythmia events (VTAs) in patients with DCM, the relationship between subepicardial or middle wall ring-like LGE and VTAs in DCM is unclear. We aimed to investigate the relationship between ring-like LGE and VTAs in DCM. Patients with DCM who underwent CMR at baseline were investigated. According to LGE distribution, patients were classified into four groups: no LGE, focal LGE, multi-focal LGE, and ring-like LGE. Ring-like LGE was defined as having at least three contiguous segments with subepicardial or mid-wall LGE in the same slice. The composite outcome was the occurrence of VTAs defined as sustained ventricular tachycardia, ventricular fibrillation/flutter, aborted sudden cardiac death (SCD), SCD and appropriate ICD intervention. The cohort comprised 157 hospitalized patients. There were 30 in no LGE group, 54 in focal LGE group, 40 in multi-focal LGE group, and 33 in ring-like LGE group. No LGE and ring-like LGE group patients were younger compared to focal and multi-focal group (p<0.001) with higher LVEF (31.6% vs. 33.0% vs. 24.4% vs. 22.1%, p<0.001). After a median of 12 (8-17) months follow up, compared to no LGE, the HRs with 95% CI for VTAs were 1.98 (0.38, 10.29), 4.57(1.00, 20.95), 9.67(2.19, 42.76) for focal LGE, multi-focal LGE, and ring-like LGE, respectively. After multivariable adjustment, ring-like LGE group remained associated with increased risk of VTAs (adjusted HR 9.84; 95%CI, 1.52, 63.47; p=0.016) independent of global LGE burden. The ring-like LGE is independently associated with an increased risk of VTAs in patients with DCM.

Impact of UV-LED photoreactor design on the degradation of contaminants of emerging concern

Recent developments in UV-LED technology open up new possibilities for water treatment. TiO2 photocatalysis can benefit from optimized photoreactor design to increase hydroxyl radical production and reduce its electrical energy per order (EEO) demands, which still ranks high among advanced oxidation processes. However, literature on UV-LED photoreactor design is largely lacking. In this work, a detailed investigation of photoreactor design is proposed. The simulation of a lab scale cylindrical reactor with 8 different UV-LED arrays was run with the professional version of an optic software. The increase of radiant flux and irradiance on the reactor’s middle cross section and side walls, respectively, was related to an increasing number of LEDs and to a shorter distance from the reactor but not necessarily to an increase in homogeneity of light distribution. A full factorial experimental design was applied to evaluate the degradation of a representative contaminant of emerging concern (ciprofloxacin) considering 4 independent variables and their interactive effects on kinetic rates and EEO values. The significance of these effects was evaluated with ANOVA and a prediction model was established. The results show that the presence of a TiO2 nanofilm was the most significant tested effect. The number of LEDs, their distance from the reactor’s wall and the adoption of controlled periodic illumination also greatly influenced kinetic rates but were less relevant for reducing EEO values because the energetic trade-off was not sufficient to turn the kinetic gain into lower electricity demands.

Simultaneous and sequential combination of electrocoagulation and ozonation by Al and Fe electrodes for DirectBlue71 treatment in a new reactor: Synergistic effect and kinetics study

In this study, the simultaneous combination of electrocoagulation and ozonation (EC-O3) was optimized in a new reactor for Direct Blue 71 treatment and compared to electrocoagulation (EC), ozonation (O3), and their sequential combination (EC→O3) by considering the performance criteria (dye and naphthalene ring removal efficiency), economic assessment (energy and anode consumption), chemical degradability, mineralization rate, and kinetic study. Applying a middle wall in the reactor improved coagulation under ozone-induced rapid mixing on the first side and flocculation under flow-induced slow mixing on the other side which reduced the floc breakage at high ozone dosages. Dye, COD, and TOC removal rate was in the following order: EC(Al)–O3>EC(Fe)–O3>EC(Al)→O3>EC(Fe)→O3>EC(Al)>EC(Fe)>O3. The synergistic effect of simultaneous combined process on dye, COD, and TOC removal were obtained 1.97, 1.42, and 1.69 for EC(Al)–O3 and 1.37, 1.14, and 1.26 for EC(Fe)–O3, respectively, which showed more ozone activation in the presence of Al ions compared to Fe ions. Also, ozone-induced corrosion for Al electrode was less than Fe electrode, which reduced anode consumption and operation cost. Finally, EC(Al)–O3 due to best performance and EC(Fe)→O3 due to optimal use of EC for decolorization and O3 for oxidation, with dye, COD, and TOC removal efficiency, energy and anode consumption, and operation cost equal to 99, 51, and 62%, 18.6 kWh m−3, 0.05 kg m−3 and 0.21 $ m−3, respectively, for EC(Al)–O3 and 99, 44.5, and 51%, 6.7 kWh m−3, 0.2 kg m−3 and 0.14 $ m−3, respectively, for EC(Fe)→O3, are suggested as suitable options for dye wastewater treatment.

Analysis of RC Framed Post Tensioned Slab Structure to Evaluate the Performance of Floating Column with and without Shear Wall using ETABS

This research aims to develop analytical study of post tensioned slab with floating column. In present scenario buildings with floating columns are of typical feature within the fashionable multi storey construction practices in urban India. Such sorts of constructions are highly undesirable in building inbuilt seismically active areas. For this buildings are given floating columns at one or more storey. These floating columns are highly disadvantageous during a building inbuilt seismically active area. The earthquake forces that are developed at different floor levels during a building got to be carried down along the peak to the bottom by the shortest path. Deviation or discontinuity during this load transfer path leads to poor performance of the building. In this paper, analytical study of post tensioned slab to evaluate the performance of floating column at ground level or at alternative story for G + 10 story building without shear wall, shear wall at corner, shear wall at center, shear wall at external middle and combined shear wall are provided for regular building is taken for study. The response of building like storey drift, storey displacement and storey shear has been wont to evaluate the results obtained using ETABS software.

Pseudo-static simplified analytical solution for seismic response of deep tunnels with arbitrary cross-section shapes

Tunnels located in seismic active areas must support not only static loads exerted by the ground under gravity but also seismic loads from earthquake events. Current analytical solutions for seismic analysis of tunnel structures are limited to circular or rectangular tunnels but not available for tunnels with other complex cross-section shapes, such as straight-wall-arch-shaped or semi-rectangular-shaped tunnels. This paper presents a unified simplified analytical solution for deep tunnels with arbitrary cross-section shapes subjected to seismic loading. Since the cross-section dimension of tunnels is normally much smaller than the wavelength of ground peak velocities, the structure can be designed using the pseudo-static approach. The ground and the tunnel liner are assumed to be elastic, homogeneous, and isotropic in plane strain condition. Two different contact conditions, no-slip and full-slip conditions, are considered at the liner-ground interface. The complex variable theory combined with the conformal mapping technique are employed to obtain closed-form solutions for tunnel deformation and stresses. The proposed solution is verified by providing comparisons between its results and those from the finite element program ABAQUS. Furthermore, parametric analyses are carried out to investigate the influence of soil-structure relative stiffness ratio, cross-section shape, height-span ratio and thickness of middle wall on tunnel responses.

Analysis of mechanical behavior of primary lining in double-arch tunnel based on distributed fibre optic monitoring

Cracking and crushing were observed in the first tunnel lining of the Kaidagu double-arch tunnel (China), excavated in weathered surrounding rock. This concrete damage occurred during excavation of the second tunnel. It was necessary to monitor the continuous strain distribution along the entire cross section of the lining. Optical fibres were attached to the inner and outer surfaces of the steel arch (primary lining) of the first lining, and monitoring was carried out during the second tunnel excavation. The overall strain distribution was obtained by the fibre optic monitoring, and the internal force and external load distribution of the primary lining were calculated using the proposed inversion analysis method. The calculation results indicated that the axial compression between the right arch shoulder and the right arch foot decreased, which could cause the internal forces of the middle partition wall to increase. The damage mechanism of the lining was inferred. For the first time, optical fibres were installed inside the lining instead of on the inner surface, and the inverse analysis method, which considered the combined effect of axial force and bending moment, was applied to the mechanical analysis of the primary lining. The calculations and analyses provided valuable information for the design and construction of similar projects.

&lt;p&gt;&lt;strong&gt;&lt;em&gt;Scutellospora deformata&lt;/em&gt;&lt;/strong&gt;&lt;strong&gt; (Scutellosporaceae), a new species of Gigasporales from the Mediterranean sand dunes of Spain&lt;/strong&gt;&lt;/p&gt;

A new species S. deformata, that occurs in six locations of marine sand dunes along the eastern Mediterranean coast of Spain is described and illustrated from spores. In the field, the species occurred in the rhizosphere of Ammophila arenaria (Poaceae), Elymus farctus (Poaceae), Otanthus maritimus (Asteraceae), and Echinophora spinosa (Apiaceae). Morphological characters related with outer, middle and inner wall of the glomerospores as well as phylogenetic analysis (partial SSU, ITS1-5.8S region and the partial LSU nrDNA) support the hypothesis that the fungus is a new species of the Scutellosporaceae.

Investigation of factors affecting thermal performance in a coal - fired boiler and determination of thermal losses by energy balance method

In this study, a coal-fired industrial type boiler's performance and emission tests were performed using the energy balance method. During the experiments, the directives in the test standard (ASME PTC - 4) were followed. This tested boiler has a capacity of 75 t/h and is used in the mining industry. This boiler is a steam drum boiler equipped with an atmospheric circulating fluidized bed furnace. The furnace chamber with a rectangular cross-section has its width of 4250 mm and a depth of 4100 mm. In order to minimize the height of the furnace chamber and whole boiler, the middle wing walls are built-in the furnace chamber. As a result of the performance test, the boiler efficiency (indirect method) was found to be 93.07% (base on the lower heating value of fuel). According to the indirect method, the first three significant losses in total boiler losses were, respectively; the conversion of H2 in the fuel to water after combustion by 4.036%, the loss of dry flue gas by 3.231%, and the proportion of unburned carbon in residual products at the end of combustion with 1.653%. Due to the fluidized bed boiler's structural characteristics, it was also shown in the test results that emissions were suppressed in the combustion chamber, which was kept in the temperature range of 850–950 °C.

Evolution of the microstructure, texture and mechanical properties of ZK60 alloy during processing by rotating shear extrusion

In this work, we use a kind of punch with a shear structure by combining torsion and backward extrusion (BE) to produce a ZK60 alloy cylinder part by rotating shear extrusion (RSE) at 643 K. This process can introduce a torsional shear component on the basis of backward extrusion by changing the direction of plastic flow and increasing the shear deformation amount to make it easier for the material at the bottom of the punch to flow to the barrel wall. Compared with BE, RSE can obviously refine grains and effectively improve the problems of a small deformation amount and insufficient flow of the material at the bottom of the back extrusion punch. The relevant microstructure evolutions of different parts of formed cylinder parts are investigated, and the results show that the proportions of dynamic recrystallization (DRX) in the inner and the middle wall of the lower half region of RSE processed part increase obviously (by 49% and 21.7%, respectively) and that the size of fine grain is ~2–4 µm; further, that of the bottom of the barrel increases by 44.6%. The deformation mechanisms of rotating shear are mainly continuous DRX (CDRX) accompanied by discontinuous DRX (DDRX) in the early stage, and with the progress of deformation, DDRX plays a leading role. The (0001) plane in the BE processed part is basically parallel to the transverse direction (TD), while the (0001) plane in the RSE part is deflected to the extrusion direction (ED) and at an angle of 30°−45° to the TD, and the texture strength is obviously weakened. A comparison of the variation in ∆Hv(%) along the TD of the barrel wall of the two extruded parts shows that RSE can generate a larger deformation amount and wider deformation effect range under the same extrusion ratio, effectively improving the microhardness of the ZK60 alloy. The ultimate strength (UTS), yield strength (YS), and elongation (EL) of alloy are ~313 MPa, ~279 MPa, ~12.1% after the RSE process, respectively. And the strength and ductility of the alloy can be improved by the RSE process.

Application of Glass Fiber Concrete under Thin-Walled Middle Partition Wall Construction in Tunnel

Aiming at the feasibility of applying glass fiber concrete as a new material to tunnel engineering, with the help of a combination of theoretical analysis, laboratory tests and engineering applications, the effect of glass fiber on the mechanical properties of concrete under different dosages and different lengths is studied. By monitoring the cracks in the middle partition wall, and applying the glass fiber to the middle partition wall in Laoshan Tunnel, to achieve the verification of the optimal length and the optimal mixing amount. The main conclusions are: (1) When the length of glass fiber is 12 mm, the tensile and compressive strength reach the maximum value; (2) Determine the optimal volume rate is 1% in order to prevent the concrete cracking effectively; (3) The crack resistance of the mid-board with glass fiber concrete is better than the ordinary concrete, which proves the feasibility of practical application of glass fiber concrete.

Analytical Solutions for the Mechanical Responses of Shallow Double-Arched Tunnel Subjected to Symmetric Loads

Double-arched tunnel is a special kind of tunnel structure which is widely adopted for shallow rock tunnels. The internal forces within a double-arched tunnel are difficult to be determined due to its special geometry and complex interactions with surrounding rock masses. This paper presents a set of analytical solutions for determining the internal forces within the lining structure of shallow double-arched tunnel subjected to symmetric external loads. The double-arched tunnel is decomposed into three main parts, i.e., the arch rings, the side walls, and the middle wall. The force method and the elastic foundation beam model are employed for the arch rings and the side walls, respectively, while the middle wall is treated as a cantilever beam fixed at the bottom. Analytical solutions for the internal forces of the three parts are derived separately, which are continuous at the conjunctions of different parts. The derived analytical solutions are verified by comparing with the FEM simulation results. Finally, parametric studies are performed to investigate the influences of burial depth, elastic resistance coefficient, opening angle, and tunnel span on the internal forces based on which some recommendations are provided for the construction and design of the double-arched tunnels. The derived analytical solutions provide fast estimations for the internal forces and deformation of the double-arched lining structures, which will be a useful tool for design optimization.

Research on Construction Methods for Ultralarge Y-Shaped Tunnel Sections

Many problems are encountered in the construction of bifurcated tunnels due the abrupt change in section, small clear distance, and large section. Progress in the direction of tunnel construction is limited by the large-span section; therefore, a special method of construction that involves constructing a guiding tunnel first followed by reverse excavation was adopted to construct the large-span bifurcation section of the Liantang tunnel of Shenzhen Eastern Transit Expressway in China. The stability criterion of the surrounding rock of the middle wall in the section of multiple arch and small clear distance is studied by theoretical analysis, and the internal stress and corresponding ultimate strength of the middle wall under different buried depths and widths of the middle wall are calculated by the stability criterion. In this study, 3D finite-difference software was used to simulate the excavation process under forward and reverse excavation conditions. The results show that the displacement field and internal force field distribution are similar for both excavation methods, and the tunneling first and reverse excavation construction method is safe and reliable.

Research on Construction Control Technology of Large-Span and Small Clear Distance Underpass High-Voltage Line Tunnel

Hanping tunnel is a control project of national highway 310 Dahejia to Qingshui highway project. It needs to cross a 330kV high-voltage transmission line under the condition of small clear distance, which requires high construction requirements. In view of the difficulties such as shallow buried depth of tunnel and small clear distance between tunnel and tower of high-voltage line, multiple excavation blasting method is adopted, and smooth blasting, charge quantity control and damping hole setting are comprehensively used to reduce the impact on the tower and structure of high-voltage line. In order to ensure the smooth progress of the project, the large-scale finite element analysis software is used to simulate the whole excavation project. The influence of the full-section method and the middle partition wall method (CD method) on the surrounding rock and the high-voltage electric tower is compared. It is found that the CD method can effectively control the displacement of the surrounding rock and the tower on it and the uneven settlement.

An Elastic Solution for Twin Circular Tunnels’ Stress in Hydrostatic Stress Field

In order to present an elastic solution for twin circular tunnels’ stress distribution in hydrostatic stress field, based on the complex variable theory and the superposition principle, the stress field of twin tunnels under static hydraulic pressure is decomposed into two parts: the original stress field and the secondary stress field. According to the symmetry of the structural form and the load distribution, the secondary stress filed can be simplifyed into a half-plane model. Therefore, the stress filed can be analyzed with the complex variable theory conveniently. Finally, the elastic solution of the twin tunnels under static hydraulic pressure is demonstrated by the superposition of the original stress field and the secondary stress field. In order to verify the analytical solution, a finite element model is adopted as the comparative test.. The result of the finite element simulation shows that the stress concentration at the middle rock wall is most obvious. And the stress concentration factor keeps increasing when the twin tunnels’ spacing distance and supporting pressure are decreasing. Besides, the maximum tangential stress appears at the tunnel boundary. The farther away from the tunnel’s boundary, the tangential stress gets lower. Furthermore, the supporting pressure leads to the increasing of radial stress and the decreasing of tangential stress. The analytical results are highly consistent with the numerical results with finite element method.