Tunnel Depth Research Articles

Monitoring, modelling and prediction of segmental lining deformation and ground settlement of an EPB tunnel in different soils

In this paper, the deformation characteristics of tunnel lining structures in different soils are studied by theoretical analysis, numerical modelling and field monitoring. The deformation of segmental lining was monitored by distributed optical fiber sensors in the tunnels of Foshan Metro Line 2 during EPB shield tunnelling. The structural deformation characteristics, including the longitudinal strain and curvature, the circumferential and longitudinal joint deformation, the longitudinal settlement, and the circumferential convergence of the tunnel under different ground conditions and at different depths are analysed based on the monitoring data. The optimized conjugate beam method is developed to analyse the lining deformation and the ground settlement. The PLAXIS 3D finite element model is utilized to study the effects of soil properties (cohesion and friction angle), tunnel depth and soil reinforcement on the tunnel lining deformation and ground settlement. Numerical modelling is further applied to simulate and predict the lining deformation of Foshan Metro Line 2 tunnels, which are compared with the monitoring data. The prediction results can effectively help to reduce the risks of large deformation and settlement in weak and soft grounds.

Estimation of Lining Pressure for Stability of Elliptical Tunnel in Cohesive-Frictional Soils

In this study, the magnitude of lining pressure required for stability of an elliptical tunnel in cohesive-frictional soil has been determined by using lower bound limit theorem in conjunction with finite elements and linear programing optimization technique. A uniform normal pressure (σi) is applied on the tunnel periphery to support the tunnel by means of lining or anchorage system. The evaluated support pressure is presented in terms of normalized pressure as σi/c acting on the periphery of a tunnel embedded in undrained cohesive and cohesive-frictional soil for different combinations of H/B, D/B, γB/c and ϕ where H is cover depth of tunnel from ground surface, B and D are width and depth of tunnel, respectively, and c, ϕ and γ are cohesion, peak friction angle and unit weight of soil, respectively.

3D centrifuge and numerical modelling of lateral responses of a vertical loaded pile group to twin stacked tunnels

Tunnel excavations inevitably induce stress release and soil movement, which may affect the safety and serviceability of nearby existing pile foundations. The effects of tunnel construction on existing piles have been extensively investigated, but little attention was paid to lateral responses of piled foundations to tunnelling. In this study, a series of three-dimensional centrifuge model tests and numerical simulations using an advanced hypoplastic soil model were carried out to investigate the response of an existing vertically loaded 2 × 2 pile group in lateral direction due to advancement of twin stacked tunnels in dry sand. In each test, twin tunnelling was simulated three-dimensionally one after the other, with the first tunnel excavated near the mid-depth of the pile shaft and the second either next to the toe of the pile group (test ST) or below but to one side of the pile group (test SB). In addition, influences of tunnel depths and locations with respect to pile group response are investigated. The most significant lateral movement of the pile cap induced after the twin tunnelling in each test. The induced bending moment and pile deflection can be critical on completion of twin tunnels in test ST. In spite of being vertically loaded pile group, the twin tunnelling caused lateral forces (shearing forces to the pile group) in each test. The calculation charts have revealed that the tunnel depth and location relative to the pile group significantly influence induced pile cap lateral displacement and pile head bending moment.

Study on the Generalized Displacement Boundary and Its Analytical Prediction for Ground Movements Induced by Shield Tunneling

The process of shield tunnel excavation would inevitably cause surrounding ground movement, and excessive displacement in the soil could lead to large deformation and even collapse of the tunnel. The methods estimating convergence deformation around tunnel opening is summarized. Then, a universal pattern of displacement boundary condition around the tunnel cavity is originally introduced, which is solved as the combination of three fundamental deformation modes, namely, uniform convergence, vertical translation, and ovalization. The expression for the above-mentioned displacement boundary condition is derived, by imposing which the analytical solution for ground movements, based on the stress function method, is proposed. The reliability and applicability of this proposed solution are verified by comparing the observed data in terms of surface settlement, underground settlement, and horizontal displacement. Further parametric analyses indicate the following: (1) the maximum settlement increases linearly with the gap parameter and the tunnel radius, while it is negatively related to the tunnel depth; (2) the trough width parameter is independent of the gap parameter and the radius, while it is proportional to the tunnel depth. This study provides a new simple and reliable method for predicting ground movements induced by shield tunneling.

Seismic response of tunnels revealed in two decades following the 1999 Chi-Chi earthquake (Mw 7.6) in Taiwan: A review

The 1999 Chi-Chi, Taiwan, earthquake (Mw 7.6) caused damage to 49 tunnels within 60 km of the epicenter, including the collapse of three mountain tunnels, ending the traditional perception that tunnels, and especially mountain tunnels, were earthquake-resistant. A series of studies that involved seismic damage investigation, physical model and numerical simulation experiments, numerical analyses and field monitoring have been carried out to investigate the damage mechanism, influencing factors and the seismic response of tunnels, and these are reviewed in this manuscript. The results of such studies over the last two decades demonstrate that tunnels suffer less seismic damage than surface structures. Most of seismic damage to tunnels involves failure of the adjacent ground or the movement of a fault that is crossed by the tunnel. Tunnel damage that is caused by ground motion occurs where the seismic effects are amplified, such as at the slope next to mined sections and portals, in shallow overburden tunnels, and at particular combinations of tunnel depth and geological conditions. Results of physical model-based tests using shaking tables and centrifuges reveal that tunnels exhibit rocking responses along with ovaling deformation or racking distortions under seismic excitation; also residual earth pressures remain on the tunnel side walls and internal forces of lining exist after shaking. The structural responses of a tunnel under non-uniform excitation are larger than that under uniform excitation. Beyond investigations of the damage mechanism and influencing factors, physical model-based tests provide experimental benchmarks for correcting numerical model settings and calibrating the characteristic parameters in numerical simulations, and validate the application of such models and simulations in the investigation of tunnel seismic responses. A fully dynamic analysis with complete descriptions of the topography and geological characteristics of a site, and the engineering characteristics of the tunnel and surrounding ground, is nowadays probably the most effective way for the seismic simulation of tunnels, and the design and evaluation of the same. An understanding of the state-of-the-art with respect to the seismic response of tunnels demonstrates the importance of three-dimensional geological models for tunnel seismic analysis; the evaluation of regional ground motion models that can capture the expected range of possible ground motions at tunnel site, and determinations of both the static and dynamic characteristics of geological conditions that are associated with site-scale vulnerabilities. Since residual earth pressures and internal forces remain on tunnel after an earthquake, the seismic damage to tunnels and loads and strain of the surrounding ground may accumulate. Methods for evaluating potential seismic damage to existing tunnels must be further developed, and more field monitoring of the seismic responses of tunnels is required. • Seismic response of tunnels revealed in past two decades is extensively reviewed. • Ground motion-induced tunnel damage occurs where the seismic effects are amplified. • Seismic damage to tunnels and loads and strain of surrounding ground may accumulate. • 3D geological models and more field monitoring are important for fully dynamic analyses.

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.

Influence of Cairo Metro Tunnel Excavation on Pile Deep Foundation of the Adjacent Underground Structures: Numerical Study

Day by day the call to solve traffic congestion problems is increasing. Subway tunnels and high-speed railway are commonly used for transportation. Therefore, tunnel construction induces soil movement, which in turn affects the stability and integrity of adjacent existing buildings. A series of numerical simulations have been established to investigate the effects of tunnel construction of the Greater Cairo Metro–Line 3-Phase-1 on adjacent pile cap foundations of Garage El-Attaba building. Many parameters have been investigated such as tunnel diameter and the distance between pile and tunnel at different tunnel axis and deep and shallow tunnel. After thorough analysis of the results’ simulation, it was found that the tunneling induces additional axial forces and bending moment as well as increasing axial settlement and lateral deflection. Moreover, the results obtained from the parametric study for the shallow and deep tunnel show that the tunnel depth has a much significant effect on piles responses. Finally, the tunnel diameter has an impact on pile responses as well as the pile cap foundation influenced by the tunnel when the tunnel is in very close vicinity of the pile, and its effect is modest to negligible if located far away from the buildings.

Anteromedial Portal Reference Technique for Femoral Tunnel Depth Measurement During Arthroscopic Anterior Cruciate Ligament Reconstruction.

Femoral tunnel preparation during the anterior cruciate ligament reconstruction is a technically demanding step. The anteromedial (AM) portal technique necessitates knee hyperflexion during the femoral tunnel reaming. In a hyperflexed knee, the arthroscopic visualization of the laser markings on the femoral tunnel reamer becomes obscured. Thus, the calculation of the depth of the femoral tunnel becomes difficult. Our technique helps in femoral tunneling reliably without the need for arthroscopic visualization using the AM portal as a reference point to calculate the depth while drilling. This technique can be performed without the need for a second assistant to hold the arthroscope. Furthermore, this technique does not require any specific instruments, and there is no obligation for an additional incision.

Study on influence characteristics of shield tunnel depth and spacing on settlement in clay strata

The surrounding ground disturbance and surface settlement induced by shield construction are the key problems of tunnelling control and necessary to be studied. Taking the shield tunnel project of Beijing Subway Line 14 as the research background, this paper studies the influence of tunnel spacing and depth on surface settlement distribution by numerical simulation method, and analyzes the relationship between the two factors and maximum settlement. The results indicate that the increase of tunnel depth or tunnel spacing leads to the decrease of the maximum settlement and the settlement reduction rate increases. With the increase of tunnel depth, the settlement trough presents approximately symmetrical distribution, and the symmetry axis is inclined to the first tunnel. With the increase of tunnel spacing, the superposition effect of twin tunnel excavation decreases, and the settlement trough transits from U-shaped to W-shaped with the maximum settlement decreasing relatively from single peak to double peaks. Also, the tunnel depth or spacing is highly correlated with the maximum settlement in a certain range, and the tunnel depth has a stronger linear correlation than the tunnel spacing. The research results provide certain theoretical guidance and references for the prediction of ground deformation and settlement control of shield construction.

Research on Influencing Factors of Reasonable Distance of Shallow Buried Close Tunnel in Weak Surrounding Rock

In order to study the influence of different spans, depths, heights and initial stresses on the reasonable clearance of shallow tunnels in weak surrounding rock. This article uses numerical simulation technology. The judging standard is whether the plastic zone of the middle rock pillar is through. The factors affecting the reasonable clear distance of the small clear tunnel are analysed. The results show that the reasonable clear distance of small-distance tunnels under shallow buried conditions gradually increases as the tunnel depth increases. The reasonable clearance distance of the tunnel increases as the lateral pressure coefficient of the surrounding rock decreases. For small-distance tunnels with the same buried depth and same span, the reasonable clearance increases as the tunnel height increases.

Effect of multi-faced twin tunneling in different depths on a single pile

In this paper, 3D modeling was performed to understand the effects of excavation of twin tunnel on a single pile in weathered residual soil. The effect of various tunnel depths on pile was evaluated in two cases of Z/Lp = 0.8 (tunnels near the pile shaft) and Z/Lp = 1.2 (tunnels below the pile tip). The effect of different patterns of the New Austrian tunneling method including top heading, central diaphragm wall, and sidewall drift on behavior of a single pile was also studied. The results of study showed that TH pattern reduced pile settlement by 36.5 and 15.9% at Z/Lp = 0.8 and Z/Lp = 1.2, respectively, compared to other patterns considered in twin tunneling. In the case of Z/Lp = 1.2, TH pattern caused the minimum magnitude of tensile force in the pile compared to other tunneling patterns. Besides, results obtained from analyses indicated that zone of influence of tunneling was independent of tunneling patterns, and it can be identified as ± 2D (D is the tunnel diameter) based on pile head settlement in longitudinal direction.

Hoek-Brown failure criterion for damage analysis of tunnels subjected to blast load

In this study, a rock tunnel subjected to blast load is modeled mathematically. For this purpose, a cylindrical shell element is used and the motion equations are derived by energy method and Hamilton's principle. In the inner surface of tunnel, different blast holes are considered and its force in radial direction is coupled by motion equations. The structural damping of the structure is assumed by Kelvin-Voigt model. Hoek-Brown failure criterion is utilized for explosion damage analysis of the tunnel. The motion equations are solved numerically by differential quadrature method (DQM). The effect of different parameters such as depth of tunnel, number and diameter of blast holes, type of stone, geological strength index (GSI) and density of stone, type and mass of explosive material are studied on the damage factor of Hoek-Brown criterion. Numerical results show that with increasing the density of explosive material, number and diameter of blast holes, the thickness of damage is increased in the tunnel. In addition, the depth of damage is decreased with increasing strength, GSI, density of rock and depth of tunnel.

Calculation of surrounding rock pressure of large section underground excavation metro station based on the construction process

The traditional calculation method of the surrounding strata pressure of the tunnel does not consider the tunnel construction process. The excavation of the large-section tunnel mostly adopts the section excavation method, which is to excavate and support at the same time. The stress state of the pressure of surrounding strata changes gradually during the excavation process. The traditional calculation results of tunnel surrounding strata pressure are generally large. In this paper, the large-section tunnel is simplified into three parts, and the degree of influence (η1, η2, η3) of the excavation height h and width b of the advance pilot hole and the distance d between the advance and rear pilot tunnels on the surrounding rock pressure calculation are analyzed. The regression equation for calculating the influencing factors (tunnel depth H, tunnel span B, internal friction angle ϕ, and rock weight γ) of surrounding rock pressure (p) is established. Through the numerical analysis, the influence coefficient η is obtained, the weight coefficient is introduced, and the computing formula of the pressure of surrounding strata of the large-section tunnel excavation is derived. The formula is used to the computing of the pressure of surrounding strata with a large-section subway station and the correct conclusion is obtained.

Limit analysis of seismic collapse for shallow tunnel in inhomogeneous ground

Shallow tunnels are vulnerable to earthquakes, and shallow ground is usually inhomogeneous. Based on the limit equilibrium method and variational principle, a solution for the seismic collapse mechanism of shallow tunnel in inhomogeneous ground is presented. And the finite difference method is employed to compare with the analytical solution. It shows that the analytical results are conservative when the horizontal and vertical stresses equal the static earth pressure and zero at vault section, respectively. The safety factor of shallow tunnel changes greatly during an earthquake. Hence, the cyclic loading characteristics should be considered to evaluate tunnel stability. And the curve sliding surface agrees with the numerical simulation and previous studies. To save time and ensure accuracy, the curve sliding surface with 2 undetermined constants is a good choice to analyze shallow tunnel stability. Parameter analysis demonstrates that the horizontal semiaxis, acceleration, ground cohesion and homogeneity affect tunnel stability greatly, and the horizontal semiaxis, vertical semiaxis, tunnel depth and ground homogeneity have obvious influence on tunnel sliding surface. It concludes that the most applicable approaches to enhance tunnel stability are reducing the horizontal semiaxis, strengthening cohesion and setting the tunnel into good ground.

Estimation of the excavation damage zone in TBM tunnel using large deformation FE analysis

This paper aims to estimate the range of the excavation damaged zone (EDZ) formation caused by the tunnel boring machine (TBM) advancement through dynamic three-dimensional large deformation finite element analysis. Large deformation analysis based on Coupled Eulerian-Lagrangian (CEL) analysis is used to accurately simulate the behavior during TBM excavation. The analysis model is verified based on numerous test results reported in the literature. The range of the formed EDZ will be suggested as a boundary under various conditions – different tunnel diameter, tunnel depth, and rock type. Moreover, evaluation of the integrity of the tunnel structure during excavation has been carried out. Based on the numerical results, the apparent boundary of the EDZ is shown to within the range of 0.7D (D: tunnel diameter) around the excavation surface. Through series of numerical computation, it is clear that for the rock of with higher rock mass rating (RMR) grade (close to 1st grade), the EDZ around the tunnel tends to increase. The size of the EDZ is found to be direct proportional to the tunnel diameter, whereas the depth of the tunnel is inversely proportional to the magnitude of the EDZ. However, the relationship between the formation of the EDZ and the stability of the tunnel was not found to be consistent. In case where the TBM excavation is carried out in hard rock or rock under high confinement (excavation under greater depth), large range of the EDZ may be formed, but less strain occurs along the excavation surface during excavation and is found to be more stable.

Инфракохлеарный доступ к верхушке пирамиды височной кости (морфометрическое исследование)

Aim: to study morphometrics data of the infracochlear tunnel on the cadaveric temporal bones, sufficient for its rehabilitation. Patients and Methods: the study was performed on 30 cadaveric temporal bones. The measurement was made using a measurement probe, a micrometer ruler, and a digital caliper. The following parameters were studied: the distances concerning the location of the facial nerve in relation to the infracochlear tunnel; the distances between the anatomical structures of the infracochlear tunnel in its various sections (from the internal carotid artery to the jugular vein); the length of the infracochlear tunnel (bisector drawn between the internal carotid artery and the jugular bulb to the basal whorl of the cochlea); the depth of the infracochlear tunnel (distance to the petrous apex from the basal whorl of the cochlea). A comparative analysis of the results obtained with the data of other scientific studies was conducted. Results: infracochlear access on the cadaveric temporal bones was performed in our study only on 18 cadaveric temporal bones (60% of cases). During surgical access to the petrous apex, a 2 mm cutter was used to avoid injury to adjacent vessels. Based on the obtained data, differences in the structure of the infracochlear tunnel were noted depending on the pneumatization of the petrous apex. The main parameters of the infracochlear tunnel have been determined, which can be applied in the choice of surgical tactics for the removal of pathological formation from the petrous apex. Conclusions: there are the following anatomical prerequisites for conducting infracochlear access to the petrous apex for its lavage: infracochlear tunnel width from 5 mm, infracochlear tunnel length from 5.5 mm, the distance between the mastoid part of the facial nerve to the anterior margin of the cochlea window from 4.8 mm. These parameters can be applied in the assessment of patients’ CT scans to determine the indications for infracochlear access to the petrous apex. KEYWORDS: petrous pyramid, petrous apex, infracochlear tunnel, infracochlear access, cadaveric temporal bones, morphometrics. FOR CITATION: Anikin I.A., Khamgushkeeva N.N. Infracochlear access to the petrous apex (morphometrics). Russian Medical Inquiry. 2021;5(7):486–491 (in Russ.). DOI: 10.32364/2587-6821-2021-5-7-486-491.

Study on deformation of surrounding rock in fault tunnel based on field measured data statistics

Based on the statistical analysis of surrounding rock deformation from 56 fault tunnels in China, the overall distribution characteristics and time evolution laws of surrounding rock deformation and the relationships with buried depth of tunnel and the height-span ratio are studied. The results of the statistical analysis show that the deformation is excessive when the tunnel passes through the fault zone. The average deformation value of surrounding rock in railway fault tunnels is maximum and second in highway fault tunnels and minimum in subway fault tunnels. The average value of peripheral convergence is larger than that of vault settlement. The deformation increases with the increases of buried depth, and the deformation in railway fault tunnels shows obvious concentration with the change of the height-span ratio. There is a significant time evolution law of surrounding rock deformation in fault tunnels, which can be roughly divided into three stages: rapid growth, slow growth and stabilization. The results offer some references for the optimal design of supporting structure and the reasonable construction time of secondary lining when the tunnels pass through the fault zone.

A Numerical Study of the Effect of Tunneling on Surface Settlement and Existing Buildings

This study aimed to determine the effect of various influencing parameters such as tunnel diameter (D), depth (H), width (B), length (L), number of floors, and the horizontal distance of the building from the tunnel axis (X), as well as soil properties such as internal friction angle (ϕ), Poisson ratio (υ), modulus of elasticity (E), and cohesion (C) on surface settlement using ABAQUS. According to the results, the settelment increases with increasing tunnel diameter at a constant depth, while it decreases with increasing tunnel depth. Changes in the width and length of the building also affect the settlement directly; consequently, as the width and length of the building increase due to increasing the cross-sectional area of the building and its rigidity and stiffness, the settlement of the foundation becomes more uniform and resistant to displacement, leading to a decrease in the surface settlement. Also, as the distance of the building from the tunnel axis increases, the settlement decreases and follows a constant trend after a distance equal to the tunnel diameter. Based on the results of the sensitivity analysis, the depth of the tunnel has the greatest effect on the surface settlement, which can be prevented by controlling the depth of the tunnel from the ground surface. Also, among the soil geomechanical parameters, the modulus of elasticity had the greatest effect on settlement in the present study. Finally, according to the results, the effect of tunnel, building, and soil properties on surface settlement is very important, particularly in urban environments.

Safe Femoral Fixation Depth and Orientation for Lateral Extra-Articular Tenodesis in Anterior Cruciate Ligament Reconstruction.

Background:Patients who undergo anterior cruciate ligament (ACL) reconstruction (ACLR) can have a persistent postoperative pivot shift. Performing lateral extra-articular tenodesis (LET) concurrently has been proposed to address this; however, LET femoral fixation may interfere with the ACLR femoral tunnel, which could damage the ACL graft or its fixation.Purpose:To evaluate the safe maximum implant or tunnel depth for a modified Lemaire LET when combined with ACLR anteromedial portal femoral tunnel drilling and to validate the safe LET drilling angles to avoid conflict with the ACLR femoral tunnel.Study Design:Descriptive laboratory study.Methods:Twelve fresh-frozen cadaveric knees were used. With each knee at 120° of flexion, an ACLR femoral tunnel in the anteromedial bundle position was created arthroscopically via the anteromedial portal using a 5-mm offset guide, a guide wire, and an 8-mm reamer, which was left in situ. A modified Lemaire LET was performed using a 1 cm-wide iliotibial band strip harvested with the distal attachment intact, to be fixed in the femur. The desired LET fixation point was identified with an external aperture 10 mm proximal and 5 mm posterior to the fibular collateral ligament’s femoral attachment, and a 2.4-mm guide wire was drilled, aiming at 0°, 10°, 20°, or 30° anteriorly in the axial plane and at 0°, 10°, or 20° proximally in the coronal plane (12 different drilling angle combinations). The relationship between the LET drilling guide wire and the ACLR femoral tunnel reamer was recorded for each combination. When a collision with the femoral tunnel was recorded, the LET wire depth was measured.Results:Collision with the ACLR femoral tunnel occurred at a mean LET wire depth of 23.6 mm (range, 15-33 mm). No correlation existed between LET wire depth and LET drilling orientation (r = 0.066; P = .67). Drilling angle in the axial plane was significantly associated with the occurrence of tunnel conflict (P < .001). However, no such association was detected when comparing the drilling angle in the coronal plane (P = .267).Conclusion:Conflict of LET femoral fixation with the ACLR femoral tunnel using anteromedial portal drilling occurred at a mean depth of 23.6 mm but also at a depth as little as 15 mm, which is shorter than most implants. When longer implants or tunnels are used, the orientation should be directed at least 30° anteriorly in the axial plane to minimize the risk of tunnel conflict, bearing in mind the risk of joint violation.Clinical Relevance:This study provides important information for surgeons performing LET in combination with ACLR anteromedial portal femoral tunnel drilling regarding safe femoral implant or tunnel length and orientation.

Research on Ground Settlement Regularity of Soft Rock Tunnel under Ultrasmall Distance

During the tunnel construction under the road, the shallower the tunnel depth, the greater the effect of the surface settlement. Thus, to analyze the ground settlement caused by tunnel construction under ultrasmall distance, the research is based on a tunnel in Ningqiang County and uses numerical simulation and measurement to analyze the ground settlement and the effect of reinforcement measures. The research draws the following conclusions. For the ultrasmall distance tunnel under road construction, the combination of pipe shed and advanced small pipe grouting reinforcement measures inhibits the surface settlement. After the advanced small pipe is reinforced, the surface settlement value is reduced by about 25%, and the reinforcement effect is more obvious after the increase of the large pipe shed. The surface settlement value is reduced by about 60%. The surface settlement caused by the excavation of the circular soil accounts for about 50%–60% of the total settlement value, which is for the whole construction. The key processes, which involve the combination of reinforcement measures, focused on the suppression of surface settlement caused by the excavation of the circular soil. After the reinforcement measures, the variation of the settlement groove width was not obvious but the curvature and peak value of the settlement groove is reduced significantly.