Full-scale performances of the slab track subgrade filled with basalt fiber-reinforced foamed concrete

Abstract

Foamed concrete has been used to address the issue of differential settlement in high-speed railway subgrades in China. However, to enhance crack resistance, reinforcement is still necessary, and further research is required to better understand the performance of foamed concrete in subgrade applications. To this end, a series of tests—including uniaxial compressive and dynamic triaxial tests—were conducted to comprehensively examine the effects of basalt fiber reinforcement on the mechanical properties of foamed concrete with densities of 700 and 1000 kg/m³. Additionally, a full-scale model of the foamed concrete subgrade was established, and simulated loading was applied. The diffusion patterns of dynamic stress and dynamic acceleration within the subgrade were explored, leading to the development of experimental formulas to calculate the attenuation coefficients of these two parameters along the depth and width of the subgrade. Furthermore, the dynamic displacement and cumulative settlement were analyzed to evaluate the stability of the subgrade. These findings provide valuable insights for the design and construction of foamed concrete subgrades in high-speed rail systems. The outcomes are currently under consideration for inclusion in the code of practice for high-speed rail restoration.

References

[1.] Gautier PE. Slab track: review of existing systems and optimization potentials including very high speed Constr Build Mater, 2015, 92: 9-15.

[2.] Li T, Su Q, Kaewunruen S. Influences of dynamic material properties of slab track components on the train-track vibration interactions Eng Fail Anal, 2020, 115: 104633.

[3.] Matias SR, Ferreira PA. Railway slab track systems: review and research potentials Struct Infrastruct Eng, 2020, 16(12): 1635-1653.

[4.] Charoenwong C, Connolly DP, Colaço A, et al.. Railway slab vs ballasted track: a comparison of track geometry degradation Constr Build Mater, 2023, 378: 131121.

[5.] Chen R, Chen J, Zhao X, et al.. Cumulative settlement of track subgrade in high-speed railway under varying water levels Int J Rail Transp, 2014, 2(4): 205-220.

[6.] Bian X, Jiang H, Chang C, et al.. Track and ground vibrations generated by high-speed train running on ballastless railway with excitation of vertical track irregularities Soil Dyn Earthq Eng, 2015, 76: 29-43.

[7.] Jiang H, Li X, Xin G, et al.. Geometry mapping and additional stresses of ballastless track structure caused by subgrade differential settlement under self-weight loads in high-speed railways Transp Geotech, 2019, 18: 103-110.

[8.] Zhai W, Wang K, Chen Z, et al.. Full-scale multi-functional test platform for investigating mechanical performance of track–subgrade systems of high-speed railways Railw Eng Sci, 2020, 28(3): 213-231.

[9.] Zhou W, Nie L, Jiang L, et al.. Mapping relation between pier settlement and rail deformation of unit slab track system Structures, 2020, 27: 1066-1074.

[10.] Cui X, Ling X. Effects of differential subgrade settlement on damage distribution and mechanical properties of CRTS II slab track Constr Build Mater, 2021, 271: 121821.

[11.] Bian X, Duan X, Li W, et al.. Track settlement restoration of ballastless high-speed railway using polyurethane grouting: full-scale model testing Transp Geotech, 2021, 26: 100381.

[12.] Ramos A, Gomes Correia A, Calçada R, et al.. Influence of track foundation on the performance of ballast and concrete slab tracks under cyclic loading: physical modelling and numerical model calibration Constr Build Mater, 2021, 277: 122245.

[13.] Cui X, Guo G, Du B, et al.. Effects of lateral differential settlement of the subgrade on deformation behavior and damage evolution of CRTS II slab track Eng Fail Anal, 2021, 129: 105674.

[14.] Chen Z, Fang H. Influence of pier settlement on contact behavior between CRTS II track and bridge in high-speed railways Eng Struct, 2021, 235: 112007.

[15.] Cai X, Zhang Q, Wang Q, et al.. Effects of the subgrade differential arch on damage characteristics of CRTS III slab track and vehicle dynamic response Constr Build Mater, 2022, 327: 126982.

[16.] Guo Y, Sun Q, Sun Y. Dynamic evaluation of vehicle-slab track system under differential subgrade settlement in China’s high-speed railway Soil Dyn Earthq Eng, 2023, 164: 107628.

[17.] Huang JJ, Su Q, Zhao WH, et al.. Experimental study on use of lightweight foam concrete as subgrade bed filler of ballastless track Constr Build Mater, 2017, 149: 911-920.

[18.] Huang J, Wang X, Fan R, et al.. Full-scale model testing of a graded crushed stone sandwich structure within the ballastless track subgrade Int J Rail Transp, 2024, 12(4): 626-647.

[19.] Shi X, Huang J, Su Q. Experimental and numerical analyses of lightweight foamed concrete as filler for widening embankment Constr Build Mater, 2020, 250: 118897.

[20.] Liu KW, Yue F, Su Q, et al.. Assessment of the use of fiberglass-reinforced foam concrete in high-speed railway bridge approach involving foundation cost comparison Adv Struct Eng, 2020, 23(2): 388-396.

[21.] Huang Z, Su Q, Huang J, et al.. Field assessment of a subgrade-culvert transition zone constructed with foamed concrete in the ballasted railway Int J Rail Transp, 2024, 12(3): 391-413.

[22.] National Railway Administration Code for design of railway earth structure, 2016 Beijing (in Chinese) China Railway Publishing House

[23.] Liu K, Su Q, Ni P, et al.. Evaluation on the dynamic performance of bridge approach backfilled with fibre reinforced lightweight concrete under high-speed train loading Comput Geotech, 2018, 104: 42-53.

[24.] Klomranok T, Su Q. Assessment of the use of polypropylene fiber reinforced foam concrete as a subgrade material for the China railway track system (CRTS) III slab ballastless tracks Transp Res Rec J Transp Res Board, 2021, 2675(11): 641-654.

[25.] National Railway Administration Code for design of high speed railway, 2014 Beijing (in Chinese) China Railway Publishing House

[26.] China Railway Society T/CRS CO602-2021: technical specification for application of cast-in-situ foamed mixture light-weight soil for earth structure of railway, 2021 Beijing China railway Publishing House

[27.] Yavuz Bayraktar O, Kaplan G, Gencel O, et al.. Physico-mechanical, durability and thermal properties of basalt fiber reinforced foamed concrete containing waste marble powder and slag Constr Build Mater, 2021, 288: 123128.

[28.] Jiang T, Wang Y, Shi S, et al.. Study on compressive strength of lightweight concrete filled with cement-reinforced epoxy Macrospheres and basalt fibers Structures, 2022, 44: 1347-1355.

[29.] Gencel O, Nodehi M, Yavuz Bayraktar O, et al.. Basalt fiber-reinforced foam concrete containing silica fume: an experimental study Constr Build Mater, 2022, 326: 126861.

[30.] Cong X, Qiu T, Xu J, et al.. Study on the effectiveness of fibre reinforcement on the engineering performance of foamed concrete Case Stud Constr Mater, 2022, 16: e01015

[31.] Bayraktar OY, Yarar G, Benli A, et al.. Basalt fiber reinforced foam concrete with marble waste and calcium aluminate cement Struct Concr, 2023, 24(1): 1152-1178.

[32.] Wang Y, Konstantinou C, Tang S, et al.. Applications of microbial-induced carbonate precipitation: a state-of-the-art review Biogeotechnics, 2023, 1(1): 100008.

[33.] Bian X, Jiang H, Cheng C, et al.. Full-scale model testing on a ballastless high-speed railway under simulated train moving loads Soil Dyn Earthq Eng, 2014, 66: 368-384.

[34.] National Railway Administration TB 10102–2023: specification for soil test of railway engineering, 2023 Beijing (in Chinese) China Railway Publishing House

[35.] Zhang C, Jiang G, Buzzi O, et al.. Full-scale model testing on the dynamic behaviour of weathered red mudstone subgrade under railway cyclic loading Soils Found, 2019, 59(2): 296-315.

[36.] Cai Y, Xu L, Liu W, et al.. Field Test Study on the dynamic response of the cement-improved expansive soil subgrade of a heavy-haul railway Soil Dyn Earthq Eng, 2020, 128: 105878.

[37.] Zhang C, Jiang G. Full-scale model testing of the dynamic response of lime-stabilized weathered red mudstone subgrade under railway excitation Soil Dyn Earthq Eng, 2020, 130: 105999.

[38.] Chen R, Zhao X, Wang Z, et al.. Experimental study on dynamic load magnification factor for ballastless track-subgrade of high-speed railway J Rock Mech Geotech Eng, 2013, 5(4): 306-311.

[39.] Lei T, Xu J, Xu L, et al.. Dynamic analysis of CRTS II ballastless track-vehicle system based on moving unit method Appl Sci, 2023, 13(11): 6566.

Funding

National Natural Science Foundation of China(52368065); China Scholarship Council(202107000077); Engineering and Physical Sciences Research Council(EP/ Y015401/1)