The northern Guangdong-southern Hainan region is located at the intersection of Eurasian Plate, Pacific Plate, and Indian Plate. Since Late Mesozoic, this region has been influenced by multiple phases of tectonic activities. Its thermal evolution history has garnered widespread attention due to its ability to constrain regional tectonic evolution process. This study has collected, compiled, and processed published low-temperature thermochronological data from northern Guangdong-southern Hainan region using inverse distance weighting(IDW) interpolation method. By analyzing the age distribution and thermal history inversion modeling results, it restores its thermal evolution history since Late Mesozoic ( approximately 150 Ma) and explores the associated tectonic process. The thermal history of Hainan Island can be broadly divided into four stages: two episodes of very rapid cooling rate at 110-90 Ma and 40-20 Ma, interspersed with two periods of thermal stability at 90-40 Ma and from 20 Ma to present. The thermal history of Guangdong Province can be broadly divided into three phases. South of Gaoyao-Huilai Fault Zone, the thermal history exhibits one phase of relatively rapid cooling at 150-80 Ma, a period of thermal stability at 80-50 Ma, and two episodic cooling after 50 Ma. Between Gaoyao-Huilai Fault Zone and Xijiang River, the thermal history shows one phase of very rapid cooling at 120-80 Ma(reaching extremely rapid cooling in some areas), followed by a phase of very rapid cooling with minor temperature fluctuations at 30-10 Ma. North of the Xijiang,the timing of the first rapid cooling stage varies across different areas, occurring at 120 -100 Ma, 80-60 Ma, and 50-30 Ma. It is noted that there is a rapid cooling period around 10 Ma in all these areas. The thermal evolution of northern Guangdong-southern Hainan region since Late Mesozoic is likely to be related to Late Mesozoic subduction of Paleo-Pacific Plate, the Early Cenozoic rollback of Pacific Plate, and the Early Eocene collision of Indian-Eurasian Plates. Additionally, Hainan Island may have been further influenced by Philippine Plate and Paleo-South China Sea tectonics.

The Proto-Tethys Ocean formed during the breakup of Rodinia supercontinent represents one of the oldest Tethyan oceans.  The Yunxian-Menghai suture zone located in western Yunnan , China is widely regarded as the site of the closure of the main Proto-Tethyan oceanic basin in southwestern Yunnan.  However , the timing of the closure of the Yunxian-Menghai Proto-Tethyan Ocean remains highly debated.  This study focuses on the mafic enclaves within the Lincang Batholith in Shuangjiang area , conducting systematic petrological , zircon U- Pb geochronological , whole-rock major and trace element , and Sr-Nd isotopic analyses.  The results reveal that the Shuangjiang enclaves are primarily composed of hornblende gabbro and gabbro-diorite.  LA-ICP-MS zircon U-Pb dating indicates an Early Silurian formation age  ( 434- 432  Ma) .  These enclaves exhibit intermediate- basic compositions , with Mg#  values ( 0. 52)  significantly  lower  than those of experimental mantle melts.  Geo- chemical characteristics show no obvious negative Eu anomalies , along with negative Ba , Nb , Zr , and Hf anom- alies and weak Sr positive anomalies.  The Sr-Nd isotopic compositions display a range from depleted to slightly enriched , with initial 87 Sr/86 Sr values of 0. 703 8 to 0. 705 6 and εNd ( t) values of - 1. 1 to 1. 2.  Integrated geo- chemical characteristics suggest that Shuangjiang enclaves are formed through fractional crystallization of partial melts derived from subduction-modified lithospheric mantle.  The emplacement of Shuangjiang enclaves indicates that the closure of Proto-Tethys Ocean occurs no earlier than the Early Silurian.

The Early and Middle Devonian paleomagnetic data of South China Block remain blank.  The Devoni- an in Guangxi is a natural laboratory for comprehensive stratigraphy.  This study carries out a series of detailed experiments of petrography , rock magnetism and stepwise thermal demagnetization of natural remanent magneti- zation on red sandstone samples collected from the Lower Devonian Lianhuashan Formation in Guanyang area , Guangxi in order to identify the mineral types , contents and assemblage characteristics , formation process of the magnetic minerals , to explore the possibility of preserving sedimentary remanent magnetization.  The results re- veal that quartz-dominated detrital grains exhibit pervasive granular dissolution pores and altered grain bounda- ries( rounded , serrated , or embayed morphologies) , indicative of intense diagenetic overprinting( replacement , dissolution , recrystallization) that severely compromises depositional remanent magnetization preservation.  Rock magnetic analyses show that the principal magnetic carriers are hematite ( dominant)  and  magnetite ,  with  up- ward-increasing magnetite contents in the interval of Lianhuashan Formation.  Critically , Mesozoic chemical re- magnetization is evidenced by Late Triassic overprints carried by hematite and secondary magnetite( derived from hematite alteration)  recording  modern  viscous  remanent  magnetization ( VRM) .  Mesozoic multiple phases of magmatic-thermal disturbance  events  make  it  extremely  difficult to obtain reliable paleomagnetic signals and magnetostratigraphic frame in Guangxi devonian.  The sampling area should be kept as far away as possible from the Mesozoic igneous rocks.

To address the complex noise characteristics inherent in measured geophysical data , the reliance of tra- ditional denoising methods on prior conditions , and the difficulty in acquiring clean labels for supervised learning , this paper introduces the Noise2Noise (N2N) unsupervised learning method.  The method aims to achieve effective denoising by  leveraging  repeated  observations or adjacent measurement points.  An N2N model is constructed based on a U-Net architecture , using multiple noisy observations as training pairs , thereby enabling network train- ing without the need for clean data.  Case studies on synthetic and field data demonstrate that , compared with tra- ditional and supervised learning denoising methods , N2N achieves superior denoising performance on both resistiv- ity and seismic data.  It not only effectively suppresses random noise in geophysical data but also handles abrupt a- nomalous data.  However , as N2N does not rely on clean labeled data , it removes not absolute noise but rather ir- regular signals ; consequently , useful signals with weak regularity may also be eliminated as noise.

Limestone slopes are highly susceptible to karstification and the detection of its karst characteristics is of great significance for elucidating water resource regulation mechanisms, karst water migration patterns, and ecological environment management in karst areas. A comprehensive method is conducted on the karst development characteristics of limestone slope in Chenqi, Puding County, Guizhou Province, integrating electrical resistivity tomography(ERT), ground penetrating radar(GPR), and geological drilling technology. A total of 7 resistivity inversion images at different positions of the slope are obtained through ERT, and the development degree of karst fissures is analyzed by integrating GPR data profiles, this research ultimately reveals the overall karst development characteristics of the study area. The results show that the karst development in limestone slope land exhibits significant spatial heterogeneity, with pipe-type karst predominantly developing in the middle of the slope land. Electrical resistivity tomography(ERT) effectively identifies the karst spatial distribution characteristics of limestone slope and by combining ground penetrating radar technology, it can further enhances the resolution of detecting karst development intensity and fracture development. Geological drilling technology is an effective mean to verify the applicability of these two methods. 

The Jurassic tectono-thermal evolution in northern Guangdong Province has generated abundant magmatic rocks, yet their petrogenetic mechanisms remain debated. This study investigates the magma source and its tectonic significance of Aizi granite in northern Guangdong by integrating LA-ICP-MS zircon U-Pb dating, trace element analysis, and zircon Lu-Hf isotopic data complemented by whole-rock Rb-Sr and Sm-Nd isotope analysis. The aim is to refine the genetic model for A-type granites formed under the Pacific Plate subduction setting during Late Jurassic. The Aizi granite yields a LA-ICP-MS zircon U-Pb age of 155±1 Ma(MSWD= 0. 12), indicating its formation during the Late Jurassic. The zircons exhibit negative εHf(t) values(-10. 4 to -4. 6), relatively high but slightly lower ( 87 Sr/ 86 Sr)i ratios(0. 713 1-0. 713 9) compared to the Mesoproterozoic basement of Cathaysia block, and zircon Hf crustal model ages(TDM2 = 1 490-1 856 Ma) that are older but marginally younger than Mesoproterozoic basement of Cathaysia block, suggesting that the magma source of Aizi granite is originated from ancient crustal materials with a small amount of mantle material added. The regional tectonic setting analysis indicates that Aizi granite is formed under the subsidence background of low-angle subduction of the Pacific plate slabs, triggered by asthenospheric upwelling that has induced partial melting of the upper crust in the weakened back-arc basin zones of Cathaysia ancient block, ultimately forming syenogranite.

The application of geological big data in 3D geological structure modeling is explored, with Chengdu taken as an example. By utilizing the achievements of geological big data in Chengdu, this paper adopts a 3D modeling method of multi-source data fusion to construct 3D geological structure models at two scales of municipal administrative region and built-up area. Through 3D model data, it extracts four important geological structural planes and geological bodies such as faults, base-cover interfaces, fine-grained soil, and pebble soil. Their 3D spatial structure change characteristics are analyzed. The research findings can provide a scientific basis for land spatial planning, underground space development and utilization, and site selection for major projects in Chengdu.

The calcite-otavite solid solution(Ca1-xCdx)CO3 is synthesized and its dissolution in air-saturated water at 25 ℃ for 270 d is experimentally explored. During dissolution, the aqueous Cd 2+ concentration increases to the peak value of 0. 082-11. 102 μmol / L in 6 h, and then declines slowly to stable state of 0. 026-1. 334 μmol / L after 210-270 d dissolution. Cd 2+ / (Ca 2+ +Cd 2+ ) mole ratio of the aqueous solution is greatly lower than Cd / (Ca+Cd) mole ratio(XCd ) of the corresponding solid showing a strong non-stoichiometric release of calcium and cadmium. At 25 ℃ , the solubility product(Ksp ) and Gibbs free energy of formation(ΔG ° f ) are determined to be 10 -8. 40±0. 02 to 10 -8. 40±0. 01 and - 1 129. 40 ± 0. 11 to - 1 129. 38 ± 0. 04 kJ/ mol for calcite ( CaCO3 ), 10 -11. 59±0. 07 to 10 -11. 51±0. 17 and -671. 61 ± 0. 45 to - 671. 18 ± 0. 99 kJ/ mol for otavite (CdCO3 ), respectively. With the increasing XCd , the Ksp value declines non-linearly from 10 -8. 40±0. 02 to 10 -8. 40±0. 01 for calcite to 10 -12. 13±0. 09 for (Ca1-xCdx)CO3 solid of XCd = 0. 90, and then increases slightly to 10 -11. 59±0. 07 to 10 -11. 51±0. 17 for otavite; while the ΔG ° f value increases linearly. Lippmann diagram is constructed for (Ca1-xCdx)CO3 solid solution with the estimated Guggenheim coefficients a0 = -2. 36 and a1 = -6. 89. The solid dissolves non-stoichiometrically and the aqueous solution moves progressively up to solutus curve and the minimum stoichiometric saturation curve for pure otavite, from right to left, finally approaches the intersection region of stoichiometric saturation curves for pure calcite and (Ca1-xCdx)CO3 solid solutions(XCd = 0. 21-0. 90). The substantially Cd-poor aqueous solution is lastly in equilibrium with CdCO3 -rich solid.

Ultra-high performance concrete( UHPC) is prepared with recycled fine aggregate( RFA) in saturat- ed surface-dry state.  The influence of RFA on the macro performance , micro performance and ecological bene- fits of UHPC is analyzed.  Under the same net water-binder ratio , different proportions of RFA are designed to replace quartz sand (0 , 10% , 20% and 30%) , and the effects of RFA on the mechanical properties , workabili- ty , hydration behavior , autogenous shrinkage and other properties of UHPC are analyzed.  The results show that the saturated surface-dry RFA can improve the workability and partial mechanical properties of UHPC.  In the meantime , with the increase of RFA , the autogenous shrinkage of UHPC is effectively reduced.  On the basis of improving macro performance , the micro performance is shown as not only the increasing cumulative heat , but also a new interface transition zone( ITZ) .  The impact of RFA on the ecological benefits of UHPC is assessed by LCA.  The introduction of RFA can effectively reduce the energy consumption of UHPC and the damage to the ecological environment.  By incorporating RFA , an excellent , eco-friendly and low-carbon cement-based materi- al is prepared.

Aiming at the engineering problems of low strength and poor water stability of silt in the Yellow River area, a curing agent(SBCG) is prepared with steel slag, granulated blast furnace slag, and desulfurized gypsum as the main materials to improve and solidify the Yellow River alluvial silt. The road performance of SBCG-solidified silt is comprehensively evaluated by standard unconfined compressive strength, water immersion softening, freeze-thaw cycles, etc. , and the internal microstructure of solidified silt is observed by SEM. The results show that the incorporation of SBCG can significantly improve the road performance of silt. The solidified silt is easier to be compacted than plain soil, and the standard curing strength of each age is significantly improved with the increase of SBCG content. The loss rate of water immersion strength at 3 d age is less than 20%. The CBR after immersion still meets the subgrade strength requirements. The residual strength ratio after melting cycle is not less than 80%. According to the change law of strength of solidified silt under different test conditions, it is determined that the content of SBCG can be controlled below 10%. The SEM images show that SBCG can be hydrated inside the silt to form a large amount of hydrated calcium silicate gel(C -S -H), which is wrapped around soil particles, and ettringite(AFt) is filled in pores, making the silt form dense cementation. The structure is beneficial to the improvement of water stability and frost resistance.

In order to build a livable city with“people-oriented and green development”, the vibrant design of urban streets is the key foundation.  Firstly , three indicators affecting the street vitality are defined from the per- spective of user psychology , 150 valid questionnaires are collected , and the reliability analysis is conducted by using Cronbach’s α .  The vitality level of the street is closely related to the three indicators by mathematical sta- tistical methods , and then the design indicator system of vibrant  street  are  established.   Secondly , the weight value of vibrant street design index is obtained after detailed analysis of the collected data by combining AHP and entropy value methods.  Finally , the Quanfeng Central Plaza in Suixi County is selected as the object to re- design the vitality  indicators ,  and  the  simulation  model  is  built  by  Analogic  software.   The  simulation  results show that the pedestrian  density  and  pedestrian flow  are  greater.   It  is  further  verified  that  the  width  of side- walks , the width of non-green belts , and the shade density are the key indicators for the vibrant street design. The design method can provide technical support for the integrated design of vibrant street.

 The expansive properties of Nanning expansive soil are improved by using marble waste powder.  The optimum dosage of marble waste powder is determined by macro test.  On this basis , the influence mechanism of marble waste powder on expansive soil expansion performance is revealed by means of micro test.  The experi- mental results show that the marble waste powder has a significant inhibitory effect on the expansion of expansive soil.  Free expansion rate , load-free expansion rate and expansion force of expansive soil decrease with the in- crease of marble waste powder content.  The best inhibition effect of marble waste powder content is 25%  on ex- pansive soil.  Combined with the limit moisture content and thermogravimetric analysis test , the change trend of the improved soil expansion with the marble waste powder content is explained from the micro perspective.  With the increase of the content of marble waste powder , the adsorption capacity of soil decreases , and the content of bound water in  soil  decreases.   Liquid  limit  and  plastic  limit  decrease  with  the decrease of  strong and  weak bound water content.   Macroscopically , the  expansion  of expansive  soil  decreases  with  the  increase  of marble waste powder content.

The ecological texture serves as the carrier and identity of the distinctive features and cultural heritage of traditional villages around scenic areas. Its degradation is irreversible, making it particularly crucial to understand its vulnerability. Using vulnerability theory, this study establishes an analytical path and assessment framework for the ecological texture vulnerability of traditional villages around scenic areas. Based on vulnerability survey data and focusing on the three elements of exposure, sensitivity, and adaptability, the mechanism of ecological vulnerability is summarized and its connotation is clarified. By integrating field surveys, quantitative analysis methods, and spatial planning theories, and through analyzing the current survival environment and state of the villages, the spatial manifestations, causes, and external driving forces of their vulnerability are examined. From the two dimensions of external and internal influencing factors, the spatial logical association of ecological texture vulnerability in traditional villages around scenic areas is constructed, and a system of influencing factors for this vulnerability is deduced. The key factors for ecological texture protection lie in the superimposed external influence of the unique tourism-driven effects from the scenic area. Under this influence, multiple key factors are formed, including the ecological and social values of the village and tourist behavior. Compared to the relatively stable factors of physical spatial conservation, these factors more prominently highlight the ecological sensitivity of traditional villages around scenic areas, enhance the sustainability of conservation for such villages, and provide rational decision-making support through suitability assessment for their revitalization and utilization.

In order to solve the problem of UHPC shrinkage, magnesite calcination is used to prepare magnesia expansion agent(MEA), and the effects of calcination temperature-holding time and calcination-powder grinding sequential relationship on the activity of MEA samples are investigated. Based on the above results, MEA samples with different activities are prepared and mixed into ultra-high performance concrete(UHPC) for compressive strength and shrinkage performance testing. The results show that the decomposition rate of magnesite increased with the increase of calcination temperature and holding time. With the increase of calcination temperature and holding time, the crystallinity of MEA becomes higher, structure will be denser, and the activity decreases. Under the same calcination temperature and holding time, the structure of MEA prepared by the burnand-grind method is sparser and more active than that prepared by the grind-and-burn method. The compressive strength and shrinkage value of UHPC decreases with the increase in the activity of MEA. When the early autogenous shrinkage of UHPC doped with 6% of the highest activity, Ⅰ-MEA1 can be reduced by 33. 31%.

To investigate the variation law of mechanical response of the graded crushed stone base stabilized with low cement content, the mechanical response characteristics of graded crushed stone structural layer stabilized with low cement content under different asphalt pavement structures are comparatively analyzed by using a meshless numerical simulation software. It is found that the mechanical parameters such as deflection and bottom stress of the new and reconstructed asphalt pavement structure changes with the difference in thickness and modulus of the low cement content stabilized graded crushed stone base. Thickness has a greater impact on bending and bottom stress than modulus, and the low cement mixing base is mainly compressive under different pavement structures. The results show that the low cement content of upper base layer improves the structural stress state of pavement, and the thickness should be controlled at about 20-30 cm, the modulus should be controlled at about 800 -1 000 MPa, and the cement content will be controlled at 2. 0%-2. 5%. In the case of ensuring the low cement content base under pressure, the deflection and tensile stress at semi-rigid structural layer should be used as the control index.

To investigate the deterioration characteristics of soil during the peak pre-failure process , a numerical model of remolded mudstone with different mineral compositions is constructed combining XRD analysis results based on GBM model.  The macro- and micro-evolution characteristics of remolded mudstone under different ini- tial moisture content conditions is explored and its pre-peak deterioration mechanisms of the mudstone are ana- lyzed.  The results indicate that the constructed numerical model , which accounts for different mineral composi- tions , has  been  validated  for  reliability  through comparison with experimental results.  The peak pre-failure process of the soil can be divided into three stages.  The failure modes of the samples primarily exhibit either shear failure or a combination of tensile and shear failures.  In Stage  Ⅲ , soil deterioration is most severe ; during this stage , the internal anisotropy coefficient of the soil is high , particle contact forces change abruptly , and the mechanical coordination number increases rapidly before stabilizing , with strength approaching the peak value. Microcracks primarily form in Stage Ⅲ , predominantly as shear microcracks within the clay mineral particles. This study provides a new approach for exploring the pre-peak failure deterioration process of soils with different mineral compositions under different initial moisture contents.

The strong thixotropy of Zhanjiang Formation structural clay causes the obvious time effect of pile foundation settlement, and there is a large error between measured value and calculated value obtained according to existing pile settlement timeliness calculation method, the applicability of existing pile foundation settlement timeliness calculation method is challenged in Zhanjiang Formation structural clay. Taking the pile foundation in Zhanjiang Formation structural clay as research object, pile foundation settlement time effect model experiment and pile side soil thixotropy experiment are carried out, the time effect coefficient of pile foundation settlement and thixotropic strength ratio of pile side soil at different standstill times are obtained, and the quantitative relationship between time effect coefficient of pile foundation settlement and thixotropic strength ratio of pile side soil is fitted. Based on hyperbolic model method, a calculation formula for time effect of pile foundation settlement considering thixotropy of Zhanjiang Formation structural clay is proposed, and the effectiveness of this calculation formula is verified by experiment and referenced data. The result shows this calculation formula can narrow the error between calculated and measured value of pile foundation settlement after a long-term load in actual project and provides a reference for the time effect calculation of pile foundation settlement in Zhanjiang Formation structural clay.

 In order to improve the efficiency and accuracy of soil moisture estimation at the regional level , a soil moisture prediction  model  based  on  MLP neural  network is proposed and compared with radial basis  function (RBF) and back propagation(BP) neural network prediction models.  Amplitude and phase are input factors , and the soil moisture value of PBO H2 O is the learning target.  The predicted value of soil moisture is obtained through iterative training by neural network model.  The results show that the three models can meet the application re- quirements in terms of reliability and prediction accuracy.  Compared with the RBF and BP models , the root mean square error of the MLP neural network model is reduced by 12. 2% and 17. 1% , respectively , and the coefficient of determination is 0. 919.  It has higher parallelism and fault tolerance , and is more consistent with the measured data .  It can be seen that this method improves the accuracy of soil moisture inversion to a certain extent , and it is feasible and effective to invert GNSS-IR soil moisture by using MLP neural network.

 In view of the instability and prolonged duration of nitrogen removal in piggery wastewater treatment system , zeolite  biofilm  suspension sphere ( ZBSS )   is  used  to design autotrophic nitrogen removal for piggery wastewater treatment.  After 27 days of acclimation , with dissolved  oxygen ( DO)  concentration which is 3. 0±0. 5 mg/L and influent nitrogen loading rate(NLR) of 0. 2 kg/ (m3   ·d) , the nitrogen ammonium removal (NAR) re- mains above 90% stably and nitrate production rate(NPR) is 0. 13 kg/ (m3   ·d) .  The ZBSS can maintain consist- ent nitritation levels.  At this time , the dominant bacterial phylum is Proteobacteria , and the relative abundance of ammonia-oxidizing bacteria is 47. 6% , and nitrite-oxidizing bacteria is not detected.  After inoculation with anam- mox sludge , DO concentration is maintained at 1. 0±0. 5 mg/L.  By coupling nitritation and Anammox into ZBSS and gradually regulating operating parameters , a ZBSS-Canon device capable of autotrophic nitrogen removal is es- tablished for the treatment of piggery wastewater.  When DO concentration is 2. 5±0. 5 mg/L and the influent NLR is 0. 86 kg/ (m3   ·d) , NRR reaches 0. 70 kg/ ( m3   · d) , and the effluent NH3 -N concentration is lower than 50 mg/L after operating for 56 days.  At this time , the relative abundance of AOB decreases , while the relative abun- dance of anammox bacteria increases.  The most dominant phylum shifts from Proteobacteria to Planctomycetota. The application of ZBSS-Canon  treatment  can  effectively  reduce  NH3 -N  as  well  as  TN  in  piggery  wastewater , thereby providing technical support for achieving stable nitrogen removal and optimizing plant remediation pond ef- ficiency.

In order to solve the problem of unknown disturbance and uncertainty in the nonlinear manipulator sys- tem , a sliding mode controller design scheme based on deep deterministic policy gradient ( DDPG)  is proposed. Firstly , the DDPG algorithm is used to make the sliding mode surface parameters in the sliding mode control dy- namically and adaptively adjust with the joint parameters to adapt to the dynamic error and external disturbance of the system.  Secondly , the adaptive proportion control is added to the controller to improve the convergence speed and control accuracy of the system.  Finally , the two-joint manipulator is selected as the research object , and the simulation experiment is carried  out  by  MATLAB/Simulink  software.   The  results  show  that  compared  with  the sliding mode controller with fixed parameters , the position tracking response time of Joint 1 and 2 of the manipula- tor under this method is reduced by 5. 71% and 56. 25% , the speed tracking response time is reduced by 6. 89% and  38. 88% ,  respectively ,  and the average position tracking error within  0. 5 s is reduced by 5. 89%  and 40. 31% , respectively , showing a better control effect.