Cumulative Settlement Research Articles

Centrifugal model test study on deformation characteristics of deep, thick fillings in giant karst cave tunnels under different construction processes

Since the deformation of deep fill is large after construction and has a great influence on the quality of geotechnical engineering, the deformation characteristics of deep, thick fill are important research topics in the field of geotechnical engineering. This study focused on a large-scale backfill project of YuJingShan tunnel on the Chengdu–Guizhou railway. Centrifugal model tests were conducted focusing on the uneven natural weak accumulation layer at the floor of the karst cave hall and the large-volume backfill of the karst cave, and test results were compared with on-site monitoring results. The deformation laws of the cave backfill and sediment layer under different construction processes, such as karst cave filling, tunnel excavation and reinforcement, and lining construction, were analyzed. The results show that: For deep, thick abandoned karst cave slag backfill without excavation and reinforcement, it would take 2.5 years to achieve deformation stability after the completion of construction of the large-scale karst cave filling. The accumulated settlement of the backfill during the construction period accounted for 82.2%–88.2% of the total settlement, whereas that of the soft soil layer accounted for 79%–88%. It would take 1.5 years to achieve deformation stability after filling and excavation. The cumulative settlement of backfill during the construction period accounted for 86.9%–92.7% of the total settlement. The settlement of the soft soil layer during the construction period accounted for 7/8 of the total settlement. When the thickness of the soft soil layer exceeded 12.5 cm, the settlement at the floor of the tunnel increased by 30%.

Long-Term Performance Assessment of a Geosynthetic-Reinforced Railway Substructure

Significant savings in carbon emissions, cost, and time could be achieved via the reduction in maintenance frequency, capital costs of track construction, and land used. Geosynthetic-reinforced soils offer such sustainable solutions. The experimental work presented in this paper investigates the long-term performance of a Geosynthetic-Reinforced Soil Retaining Wall (GRS-RW) system as an alternative to the conventional railway embankment. Full-scale testing was carried out on three sleeper sections of ballasted and slab tracks by simulating train loads cyclically, phased to 360 km/h. The tracks were supported by either a low-level fully confined conventional embankment or a GRS-RW substructure. The substructures were formed of a 1.2 m deep subgrade and frost protection layer, in accordance with high-speed railway design standards. The overall aim was to assess the performance of the tracks, in terms of transient displacements and total settlements. It was observed that once the GRS-RW system reached its active state, it deformed in a very similar way to a conventional embankment despite the fact that the GRS-RW system is less confined than the conventional embankment. The results indicate that the cumulative settlement of the slab track, which is due to the plastic deformation of the soil, is significantly less than that of the ballasted track, which is primarily caused by the movement of the ballast particles.

Experimental study on the behavior of single pile foundation under vertical cyclic load in coral sand

The bearing behaviors of piles in coral sand are critical for project safety due to the unique physical and mechanical properties of coral sand, such as high void ratio, high compressibility, high friction angle and easy to break. A series of model experiments were carried out in this study to evaluate the vertical behavior of single pile in coral sand foundation under cyclic dynamic load with the consideration of the influence of the amplitude of cyclic load, the static biased load and the number of cyclic. Load-settlement relationships, settlement-cyclic number relationships, pile tip and pile side resistances have been thoroughly investigated. Results showed that the load in coral sand foundation will transfer to the pile tip more obviously compared with the pile foundation in quartz sand. Therefore, the pile side resistance will be reduced while the corresponding pile tip resistance will be increased. Particularly, the weakening of side resistance mainly occurs in the first 500 cycles. The development of cyclic cumulative settlement is affected by the combination of the magnitude of static biased load and cyclic amplitude. The existence of static biased load is conducive to restrain the cyclic cumulative settlement when the amplitude of cyclic load is less than static load.

Parameters of dynamic compaction based on model test

Several large–scale outdoor dynamic compaction model tests with energy levels, drop distances, masses and diameters of falling weight as variables, and different types of acceleration sensors are respectively designed in this paper to monitor inside soil mass, ground surface and falling weights dynamically. The following results are presented: the soil damping ratio changes with the increase of tamping times; at the same energy level, the horizontal reinforcement effect of a heavy falling weight on shallow and deep soil is better than a light falling weight and the ground surface vibration caused by heavy falling weight is small; the combination of tamping impulse and falling weight diameter is appropriate as the control standard of final cumulative settlement; the construction and detection of dynamic compaction can be assisted by the statistical relationship between the tamping impulse I, the impact time T and the single tamping settlement y. The results of this study are instructive for improving the construction quality of dynamic compaction.

Investigating characteristics of the long-term settlement of railway embankments in warm permafrost areas

Introduction: The embankment in the permafrost zone of the Qinghai–Tibet Railway (QTR) faces the problem of permafrost degradation, especially in the warm and ice-rich permafrost areas. The settlement deformation of the embankment is more serious in these areas.Methods: This study systematically investigates the settlement deformation characteristics during 16 operational years of three types of typical roadbed structures. The traditional embankment (TE), U-shaped crushed-rock embankment (UCRE), and crushed-rock revetment embankment (CRRE) are the roadbed structures. The long-term monitoring ground temperature and deformation data of the embankment section along the QTR in warm permafrost areas from 2005 to 2020 are utilized in analysis.Results and Discussion: This study focuses on the influence law of the roadbed structure form, shady–sunny slope effect, and temperature field change on the settlement of the roadbed. The results indicated that the two types of the crushed-rock embankment (CRE) of the long-term cumulative settlement are less than 50% of the cumulative settlement of the TE, and the impact on controlling the settlement is significant. The annual settlements of the three types of embankment structures are related to the artificial permafrost table (APT) and influenced by cyclical climate change at the regional scale. The annual growth rate of the settlement at the left and right shoulders of the UCRE as a result of the effect of the shady–sunny slope does not vary considerably as the number of operational years increases. The impact of the shady–sunny slope on the CRRE for the various settlements before 2008 was negligible. After 2008, the thermal disturbance to the embankment temperature field induced by the preconstruction and the effect of shady–sunny slopes decreased gradually as the number of operational years increased. In some years of operation, a thawed interlayer in the TE and CRRE greatly affected the embankment settlement acceleration. The settlement growth rate of the TE is related to the decline of the artificial permafrost table (APT). During the operational years, there was no thawed interlayer in the UCRE. The development of the settlement rate is unaffected by the temperature field for either the left or right embankment shoulder.

Experimental Study on the Dynamic Characteristics of a New Long-Short Pile Composite Foundation under Long-Term Train Load

Long-short pile composite foundation (PC-LSPCF) composed of part-screw pile and cement-soil compaction pile is a new railway foundation treatment method, which has been widely used in high-speed railway construction projects in China. To explore the dynamic characteristics and deformation characteristics of railway PC-LSPCF under long-term train loads, the dynamic characteristics of long piles, short piles, and soil between piles under long-term train loads are tested by an indoor dynamic model test. The dynamic amplification of pile and soil under dynamic load and the temporal and spatial distribution of peak response are analyzed, and the stress and deformation development mechanism of PC-LSPCF under cyclic loading of large-cycle trains is revealed. The results show that the neutral point of the long pile is at 1/2 of the pile length and that of the short pile is at 3/8 of the pile length. The part-screw pile has a certain absorption effect on vibration energy. The deformation of a long-short pile composite foundation under long-term train loads can be divided into three stages: extreme growth, transition, and stability. The train speed is negatively correlated with the cumulative settlement of the long-short pile composite foundation. The higher the train speed, the smaller the cumulative settlement, and the smaller the number of cycles of the N-S curve entering the gentle period. As the number of train cyclic loads increases, the load-sharing relationship of the long pile-short pile-soil system will be redistributed. The research results have important reference significance for the optimization design of high-speed railway foundation treatment.

Recovery of longitudinal deformational performance of shield tunnel lining by soil Grouting: A case study in Shanghai

This paper presents a case study introducing the effect of soil grouting conducted to repair the longitudinal performance of shield tunnel in Shanghai. The maximum of cumulative settlement of the shield tunnel was approximately 15 mm with an averaged increasing rate as high as 0.50 mm/d caused by a new tunneling project underneath. The grouting reinforcement for soils under the invert of tunnel was thus carried out in the distorted section. A full process of deformational responses in terms of settlement and horizontal convergence to the grouting was measured to analyze the influence of grouting on performance recovery in the longitudinal direction. Volume-based grouting efficiency was defined for evaluating the contribution of grouting to structural deformation recovery. The results showed that the settlement is reduced linearly with the increasing of grouting volume. However, horizontal convergence increased during the grouting process and the maximum convergence increment was about 63 % of the magnitude of settlement reduction. Meanwhile, grouting efficiency was found to be relatively low. An average of 9.03 % of the grout volume is contributed to the recovery of settlement trough, while 2.75 % acted on the increase of convergence. Besides, continuous grouting can effectively recover tunnel settlement and remain a safe state.

Experimental investigation on the reinforcement of a high-pressure jet grouting pile for an ultra-shallow tunnel in a strongly weathered stratum

In this paper, the performance of a high-pressure grouting material and consolidation body, the key parameters of tunnel surrounding rock reinforcement, and the field reinforcement effect are compared and studied. The results show that 1) the compressive strength, elastic modulus, and seepage resistance of the consolidation body are related to the water–cement ratio. The permeability of the consolidation body increases with increasing water–cement ratio under the constant head; under the condition of a certain water–cement ratio, the strength increases with an increase in cement content. To meet the construction requirements and the slurry stability, a small water–cement ratio is appropriate. 2) Slurry pressure, rotary spray speed, and lifting speed on the single pile static load bearing capacity have a significant impact. Under the same static load conditions, the greater the slurry pressure, the lower the cumulative settlement value of the single pile, the cumulative settlement value increases less, and the amount of change in rebound is the same; with the increase in the rotational speed of the rotary spray, the lower the cumulative settlement value of the single pile, and the rate of change of the cumulative settlement value of the single pile decreases; and with the increase in the lifting speed, the cumulative settlement value of the single pile increases and the rate of change of the cumulative settlement value decreases. 3) The pile body cement soil is more uniform, has high strength, and is brittle, and the stratum where the slurry part is located is a loose powder clay layer and sandy layer. 4) After high-pressure jet grouting pile reinforcement, the top surrounding rock is more stable after the excavation of an ultra-shallow buried tunnel, the fissures between the surrounding rocks are filled with cement soil consolidation, and the integrity is improved. Certain piles also play a certain role in stopping water; high-pressure jet grouting pile reinforcement to improve the integrity of the surrounding rock played a role in consolidating the weak soil layer above the tunnel vault, creating conditions for the safe excavation of the shallow buried section of the tunnel.

Application of the Richards Model in Settlement Prediction of Loess-Filled Foundations

The Richards equation has high plasticity and compatibility. Compared with other curve equations, it has higher applicability and accuracy in describing S-shaped curves. It can describe the changes in the initial growth stage, rapid growth stage, and stable growth stage of organisms well and reflect the slow-fast-slow change characteristics of growth. In this paper, the Richards model is introduced into the settlement deformation prediction of loess-filled foundation. Taking a high-loess fill site in northern Shaanxi Province as an example, continuous settlement deformation monitoring is carried out for the filling during the project operation period, and the settlement characteristics of a loess-filled foundation are studied using the monitoring results. It is considered that the settlement deformation curve of a loess-filled foundation has similar characteristics; that is, its deformation increases slowly in the early stage, rapidly in the middle stage, and is basically stable at a fixed value in the later stage. Its cumulative deformation time history curve is a smooth S-shaped curve, and the cumulative settlement increases with time and tends to converge. Analysis shows that the time history curves of cumulative settlement, the settlement deformation rate, and the acceleration of loess foundation filling are highly consistent with the Richards model. Compared with the modified exponential model and hyperbolic model, the predicted results are closer to the measured results; that is, the Richards growth model can be used to predict the settlement deformation of a fill foundation.

Geotechnical performance of fine tailings in an oil sands pit lake

Syncrude Canada Ltd.’s Base Mine Lake (BML), the first commercial-scale demonstration of an oil sands pit lake, was commissioned in December 2012, following in-pit deposition of fine tailings (FT) between 1995 and 2012. The geotechnical design basis for the FT in BML is that it will consolidate and densify over time, contributing to fines sequestration below the water cap. This paper presents the geotechnical performance of the FT in BML within the context of this geotechnical design basis. The FT has settled from 196.0 to 171.6 Mm3 by 2019, with cumulative settlement varying spatially between 0.3 and 6.7 m. FT settlement is consistent with the expected self-weight consolidation as modeled by finite-strain non-linear consolidation theory, and is reflected as temporal increase in the profiles of solids content and effective stress. Sonar surveying, profile sampling, shear strength, and underwater photography show that the transition of geotechnical properties at the mudline becomes increasingly distinct over time. These observations support the geotechnical design basis for BML and indicate the fines continue to be sequestered below the water cap.

Numerical Analysis of the Influence of Foundation Replacement Materials on the Hydrothermal Variation and Deformation Process of Highway Subgrades in Permafrost Regions

Affected by global warming, permafrost thawing in Northeast China promotes issues including highway subgrade instability and settlement. The traditional design concept based on protecting permafrost is unsuitable for regional highway construction. Based on the design concept of allowing permafrost thawing and the thermodynamic characteristics of a block–stone layer structure, a new subgrade structure using a large block–stone layer to replace the permafrost layer in a foundation is proposed and has successfully been practiced in the Walagan–Xilinji section of the Beijing–Mohe Highway to reduce subgrade settlement. To compare and study the improvement in the new structure on the subgrade stability, a coupling model of liquid water, vapor, heat and deformation is proposed to simulate the hydrothermal variation and deformation mechanism of different structures within 20 years of highway completion. The results show that the proposed block–stone structure can effectively reduce the permafrost degradation rate and liquid water content in the active layer to improve subgrade deformation. During the freezing period, when the water in the active layer under the subgrade slope and natural ground surface refreezes, two types of freezing forms, scattered ice crystals and continuous ice lenses, will form, which have different retardation coefficients for hydrothermal migration. These forms are discussed separately, and the subgrade deformation is corrected. From 2019 to 2039, the maximum cumulative settlement and the maximum transverse deformation of the replacement block–stone, breccia and gravel subgrades are –0.211 cm and +0.111 cm, –23.467 cm and –1.209 cm, and –33.793 cm and –2.207 cm, respectively. The replacement block–stone subgrade structure can not only reduce the cumulative settlement and frost heave but also reduce the transverse deformation and longitudinal cracks to effectively improve subgrade stability. However, both the vertical deformation and transverse deformation of the other two subgrades are too large, and the embankment fill layer will undergo transverse deformation in the opposite direction, which will cause sliding failure to the subgrades. Therefore, these two subgrade structures cannot be used in permafrost regions. The research results provide a reference for solving the settlement and deformation problems of subgrades in degraded permafrost regions and contribute to the development and application of complex numerical models related to water, heat and deformation in cold regions.

Study on safety and stability of high altitude dump under severe drying-wetting alternation.

This study aimed to reveal the impact of the severe drying-wetting process on the safety and stability of high-altitude dumps. Numerical calculations were conducted for the open mining dump of limestone mines for cement in high-altitude mining areas. The distribution law equation of the matric suction and the shear strength equation were imported for unsaturated soil based on the unsaturated-saturated seepage theory. Therefore, the evolution characteristics of the unsaturated-saturated seepage field and the stability of the dump were studied under severe drying-wetting. The results indicated the following rules: As the intensity of the wetting-drying alternation increased, the surface soil on the dump changed from an unsaturated to a saturated state, the matric suction continued to decrease until it reached zero, the shear strength decreased, and the unsaturated area shrank. The dump slipped under the influence of the drying-wetting alternation, the sliding area was the dump itself, and developed to the deep layer as the intensity of the drying-wetting alternation strengthened. The cumulative settlement value of the dump increased with time and eventually stabilized, and the maximum accumulative settlement value calculated by simulation was in good agreement with the actual monitoring value. The safety factor decreased as the intensity of the drying-wetting alternation increased.

Correlating severe land subsidence and confined brine aquifer compaction in the Yellow River Delta, China, with Sentinel-1A/1B satellite images

In recent years, noticeable subsidence depressions have occurred along the coastal zone of the Yellow River Delta. In some coastal areas, the average annual subsidence varies from tens of millimeters to hundreds of millimeters. Although some studies have discovered a significant land subsidence funnel in the coastal zone of the Yellow River Delta, it has rarely been reported in recent years. Using Sentinel-1A/1B images from the last five years and permanent scatterers interferometric synthetic aperture radar technology, we found a typical subsidence bowl in the northeastern part of the delta, with a cumulative settlement of nearly 1 m over five years. In addition, we used the approach of soil mechanics to simulate the settlement of confined brine layers with different thicknesses under drainage conditions. We found that the 15 m thick confined aquifer can produce 1 m of settlement for every 15% decrease in water content. The simulation results explain the large settlement of the brine industrial area. This study can provide guidance for brine mining in the future. If we continue to overexploit underground brine, there will be more severe land subsidence in the delta in the future.

Study on the In Situ Test of the Treatment Effect for the Riverbank Soft Soil Subgrade in the Hetao Area

The Inner Mongolia Hetao area has a widely distributed riverbank fluvial soft soil with high groundwater levels and ground surface water. This situation may incur some potential engineering problems for the Linhe-Baigeda section of the Beijing-Xinjiang Expressway, such as subgrade settlement control and waterproofing. In situ experiments were conducted on the site using five subgrade base treatment schemes for subgrade construction. The long-term monitoring of various technical indicators like settlement, earth pressure, pore water pressure, and reinforcement material deformation was carried out. Study results show that the cumulative settlement generated when the double-layer geogrid reinforces the subgrade base is 6.9 cm, which is the smallest among the five subgrade base reinforcement methods, and the cumulative settlement of the subgrade base reinforced with a single-layer geocell is the largest, which is 15.4 mm. The size and distribution of subgrade earth pressure change significantly during farmland irrigation. When the single-layer geocell reinforces the base, the subgrade stress is smaller than that of the other four, and the average earth pressure is 8 kPa. The membrane-pulling effect of reinforcement material significantly disperses the upper load of subgrade backfill soil, and the subgrade settlement control with different base treatment schemes meets the technical requirements.

SPATIAL VARIABILITY OF GAS COMPOSITION AND FLOW IN A LANDFILL UNDER IN-SITU AERATION

In-situ aeration of landfills accelerates biodegradation of waste organic matter and hence advances waste stabilization. The spatial outreach of aeration greatly affects stabilization efficiency. This study analyzed the spatial variability of gas composition and flow in 230 wells spread over four compartments of a Dutch landfill which is under in situ aeration since 2017, as well as the carbon extraction efficiency, temperature, and settlement. Flow rates and gas composition in the extraction wells varied strongly. The highest variability was observed in the compartment with the highest water tables with submerged filter screens for most wells, with low flow rates, and elevated ratios of CH4 to CO2, indicating predominance of anaerobic processes (compartment 11Z). The compartment with the most uniform distribution of gas flow rates, composition and lower ratios of CH4 to CO2, suggesting a significant share of aerobic carbon mineralization, also showed higher temperatures, a carbon extraction efficiency, and larger cumulative settlement, all indicative of enhanced microbial activity (compartment 11N). In this compartment, the amount of extracted carbon exceeded the carbon generation predicted from landfill gas modeling by the factor of 2 over the hitherto four years aeration. The effect of water tables on gas flow and the correlation between the flow, and the ratio of CH4 to CO2 appeared weak, indicating that also other factors than water tables influence gas concentration and flow. Future work includes stable isotope probing to analyze the significance of microbial respiration and microbial CH4 oxidation for the composition of the final extracted gas mixture.

Performance and Application of Geocell Reinforced Sand Embankment under Static and Cyclic Loading

As reinforcement material, geocells are widely used in various types of embankment reinforcement. A lot of practical experience shows that geocell reinforced embankment has good reinforcement effect, but the theoretical research lags behind the engineering practice, and the reinforcement mechanism under cyclic loading under various reinforcement conditions needs to be further studied. In this paper, the reasonable reinforcement condition of geocell reinforced embankment under static and cyclic loading is proposed by using a physical model and numerical simulation comparative analysis method. The research findings include: under cyclic loading, the inhibition effect of the number of reinforced layers on the vertical cumulative settlement is better than that under static loading, but the effect of two-layer reinforcement and three-layer reinforcement is relatively close, and both can reduce the vertical settlement by more than 40%. The inhibition effect of the increase of geocell height on the horizontal deformation of slope surface is better than that of the decrease of welding spacing under cyclic loading, and the reinforcement effect of the middle and upper part of embankment is better. Increasing the height of geocell and reducing the welding spacing can improve the limit bearing capacity of embankment, and the former is better. The optimal reinforcement condition of sandy soil embankment under cyclic loading obtained from the comparative analysis is case 3, that is, the reinforced layers is 2, the geocell height is 10 mm, and the welding distance is 50 mm.

Model Test of Bearing Characteristics of Fly Ash Foundation under Cyclic Loading

Based on the vertical cyclic model test of the cement-fly ash mixing pile (CFMP) composite foundation, the effects of different dynamic load ratios on the long-term bearing characteristics of the composite foundation were studied. From the perspectives of foundation cumulative settlement, dynamic stiffness, pile axial force, and pile lateral friction, etc., the bearing mechanism of the CFMP fly ash composite foundation under cyclic load was investigated. By virtue of the assay herein, the authors discovered that the cumulative settlement under different load ratios exhibited the “threshold effect”, which could be divided into the attenuation type and destruction type. When the peak value of the cyclic load was close to the ultimate bearing capacity, the dynamic failure of the pile foundation occurred. The cyclic displacement ratio ranged from 1.05 to 1.23, satisfying the relation of quadratic equation. The cyclic load settlement could be predicted by the static load displacement. During cyclic loading, the proportion of the pile side sharing the upper load decreased persistently, and the fatigue degradation of side friction resistance occurred. The degradation could be alleviated by reducing the water content of fly ash and taking waterproof measures during construction.

Automated Particle Shape Identification and Quantification for DEM Simulation of Rockfill Materials in Subgrade Construction

Rockfill materials, conducted by impermeable stone, are frequently used in subgrade construction projects. The irregularity and variability of particle shape are demonstrated to affect the mechanical properties of rockfill subgrade, such as void ratio and coordination number. This study first identifies the subgrade rockfill particle contour by machine learning algorithms, including AdaBoost, Cascade, and sliding windows. Then, the shape evaluation indexes of length flatness, edge angle, and roughness are quantified, and the statistical analysis of each index is presented. In addition, the discrete element method (DEM) simulation is implemented on the compaction of rockfill subgrade to explore the impact of roundness on characteristics of particles. Finally, the macroanalysis on the void ratio and cumulative settlement and the microanalysis on particle coordination number, rotation momentum, and displacement are studied. The results illustrate that roundness has a significant effect on the mechanical characteristics of subgrade rockfill materials. With the increase of rolling passes, the porosity of packing decreases, whereas the settlement increases gradually. The change rate starts fast and ends slowly.

Monitoring and Prediction Analysis of Settlement for the Substation on Soft Clay Foundation

The bearing capacity of soft clay foundations is low, which easily causes excessive cumulative and uneven settlement of the substation. This will seriously threaten the safe operation of equipment in the substation. Based on a 220‐kV substation project in a coastal soft clay ground, the settlement of the substation building is monitored on the spot, and the settlement law of soft clay ground is analyzed. Furthermore, a three‐dimensional finite element model is developed using finite element software named ZSOIL.PC. A numerical model for predicting the settlement of soft clay ground in a substation is proposed using the appropriate element type, material constitutive model, and calculation parameters. The rationality of the numerical method is validated by comparison with the measured data. After improving the soft clay ground with the cement‐soil deep mixing method, there are still certain degrees of cumulative and differential settlements in the substation distribution device building, but both are within the specification requirements. The settlement of the soft soil ground in the substation increases with time, but the growth rate gradually decreases and ultimately tends to stabilize after a certain period of time, ensuring the uniformity of foundation treatment is the key to controlling the differential settlement. The research results can provide a reference for the subsequent installation and construction of electrical equipment and the design of substation engineering in soft soil ground.

Experimental study on thermal-mechanical properties of energy pile in saturated clay foundation

Based on the laboratory model test， the thermal-mechanical response of the energy pile in saturated clay foundation under multiple temperature cycles was studied. The temperature field around the pile， the settlement of pile and soil， the additional heating stress of pile and the shaft friction were analyzed. The results show that the temperature of pile and soil decreases along the depth and radial direction respectively， when the temperature rises. The settlement of pile top caused by cooling is greater than the expansion caused by heating. The heat transfer liquid was heated from 5 ℃ to 70 ℃， then maintained for 24 h， and then cooled to 5 ℃ for 5 h. This cycle for 3 times results in irreversible cumulative settlement of pile top. The settlement decreases with the distance from the pile， and the sedimentation rate of the soil decreases with the increase of the number of cycles. After three cycles， the settlement of soil surface 130 mm away from pile side reaches 1.42% of diameter of pile. The additional stress and the shaft friction of pile caused by temperature load increase gradually with the increase of temperature and number of cycles. The maximum additional heating stress reaches 695.40 kPa under working load， and the value varies with the change of pile top constraint condition， and its position moves gradually upward with the increase of the load on pile top. When heating， the negative shaft friction occurs in the upper part of the pile and the positive shaft friction occurs in the lower part. When cooling， the results are just the opposite. Under the action of the working load， the negative shaft friction area of the pile becomes smaller， and the zero-displacement point moves upward gradually. <fig fig-type="abstract-image" id="F1" orientation="portrait" position="float"><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="SP.J.1249-2022-39-1-85/9857FEDA-6661-4785-AADA-D5A71C0EB8A5-F001.jpg"/></fig>