Mechanical properties and fracture surface roughness of thermally damaged granite under dynamic splitting

In order to understand the mechanical properties and the fracture surface roughness characteristics of thermally damaged granite under dynamic splitting,dynamic Brazilian splitting tests were conducted on granite samples after thermal treatment at 25,200,400,and 600℃.Results show that the dynamic peak splitting strength of thermally damaged granite samples increases with increasing strain rate,showing obvious strain‐rate sensitivity.With increasing temperature,thermally induced cracks in granite transform from intergranular cracks to intragranular cracks,and to a transgranular crack network.Thermally induced damages reduce the dynamic peak splitting strength and the maximum absorbed energy while increasing the peak radial strain.The fracture mode of the thermally damaged granite under dynamic loads is mode Ⅱ splitting failure.By using the axial roughness index Z2 a,the distribution ranges of the wedge‐shaped failure zones and the tensile failure zones in the fracture surfaces under dynamic Brazilian splitting can be effectively identified.The radial roughness index Z_(2)^(r)is sensitive to the strain rate and temperature.It shows a linear correlation with the peak splitting strength and the maximum absorbed energy and a linear negative correlation with the peak radial strain.Z_(2)^(r)can be used to quantitatively estimate the dynamic parameters based on the models proposed.

Granite thermal reservoirs in Lingshui area of Hainan Island and their significance to geothermal resources,China

Hainan Island located at the southernmost tip of the continental crust of the South China Plate,has high terrestrial heat-flow values,widely-distributed hot springs,and rich geothermal resources.Intensified researches on the origin and potentials of geothermal resources can promote Hainan Island's development into a clean energy island.To determine the geological conditions for the formation of geothermal resources in southern Hainan Island,we collected core samples of granites from the Baocheng batholith in southern Hainan Island and conducted systematic analysis in respect of petrology,geochronology,geochemistry,and petrophysical property.The results of this study are as follows.The Baocheng batholith in the southern Hainan Island has a crystallization age of 98.42±0.56 Ma,making it the product of magmatism in the early stage of the Late Cretaceous.It mainly consists of high-K calc-alkaline granites,which were intruded by intermediate-to-mafic veins.The Baocheng batholith has a high radioactive heat generation rate of 2.712-6.843μW/m^(3),with an average of 3.846μW/m^(3),a radioactive heat-flow value of 30.768 μW/m^(2)and a heat-flow contribution rate of 38.95%-43.95%.As shown by the results of their thermophysical property analysis,the granites have high thermal conductivity and can serve as highquality geothermal reservoirs.In combination with previous geological and geophysical data,the geothermal model of the Lingshui area was established in this study.The deep structure indicates the presence of high-conductivity and low-resistivity layers in the basement of the Baocheng batholith.It can be inferred thereby that asthenospheric upwelling may occur and that there exist two magma vents at depth in the batholith.Therefore,magmatic heat at depth and granites with high radioactive heat generation rate serve as the main heat sources in the Lingshui area.

Comparison of mechanical properties in high temperature and thermal treatment granite

Static mechanical experiments were carried out on granite after and under different temperatures using an electro-hydraulic and servo-controlled material testing machine with a heating device. Variations in obvious form, stress-strain curve, peak strength, peak strain and elastic modulus with temperature were analyzed and the essence of rock failure modes was explored. The results indicate that, compared with granite after the high temperature treatment, the brittle-ductile transition critical temperature is lower, the densification stage is longer, the elastic modulus is smaller and the damage is larger under high temperature. In addition, the peak stress is lower and the peak strain is greater, but both of them change more obviously with the increase of temperature compared with that of granite after the high temperature treatment. Furthermore, the failure modes of granite after the high temperature treatment and under high temperature show a remarkable difference. Below 100 ℃, the failure modes of granite under both conditions are the same, presenting splitting failure. However, after 100 ℃, the failure modes of granite after the high temperature treatment and under high temperature present splitting failure and shear failure, respectively.

Effect of thermal treatment on energy dissipation of granite under cyclic impact loading

High temperature treatment causes thermal damage to rocks in deep mining.To study the thermal effect on the energy dissipation of rocks during the dynamic cyclic loading,cyclic impact loading experiments of heat-treated rocks were carried out using the splitting Hopkinson pressure bar(SHPB)experimental system.The correlations among the energy dissipation,energy dissipation rate,impact times,accumulated absorbed energy per volume,failure mode and temperature were analyzed.The results show that the reflected energy under the first impact increases and finally exceeds the absorbed energy when the temperature increases;however,the total reflected energy decreases above 200℃.The absorbed energy under the first impact and the total absorbed energy all decrease as the temperature increases,the rates of which decrease accordingly.And the same phenomenon appears for the transmitted energy and the rate of the transmitted energy.On the contrary,the rate of the reflected energy increases with the rising temperature.When the temperature increases,the fewer impact times are needed to destroy the sample.In addition,the failure modes are different when the rock is treated at different temperatures;that is,when the temperature is high,even though the absorbed energy is low,the sample breaks into powder after several impacts.

Evolution of deformation property and strength component mobilization for thermally treated Beishan granite under compression

The cohesion weakening and friction strengthening(CWFS)model for rock reveals the strength components mobilization process during progressive brittle failure process of rock,which is very helpful in understanding mechanical properties of rock.However,the used incremental cyclic loading−unloading compression test for the determination of strength components is very complicated,which limits the application of CWFS model.In this paper,incremental cyclic loading−unloading compression test was firstly carried out to study the evolution of deformation and the strength properties of Beishan granite after various temperatures treated under different confining pressures.We found the axial and lateral unloading modulus are closely related to the applied stress and damage state of rock.Based on these findings,we can accurately determine the plastic strain during the entire failure process using conventional tri-axial compression test data.Furthermore,a strength component(cohesive and frictional strength)determination method was developed using conventional triaxial compression test.Using this method,we analyzed the variation of strength mobilization and deformation properties of Beishan granite after various temperatures treated.At last,a non-simultaneous strength mobilization model for thermally treated granite was obtained and verified by numerical simulation,which demonstrated the effectiveness of the proposed strength determination method.

Numerical modeling of thermal breakthrough induced by geothermal production in fractured granite

It is well known that the complicated channeling of fluid flow and heat transfer is strongly related with the intricate natural fracture system.However,it is still challenging to set up the fracture network model which is strong heterogeneous.Compared with other methods(e.g.equivalent continuum model(ECM),discrete fracture model(DFM),and ECM-DFM),the fracture flow module in the COMSOL Multiphysics simulator is powerful in definition of fractures as the inner flow boundary existing in the porous media.Thus it is selected to simulate the fluid flow and heat transfer in the geothermal-developed fractured granite of Sanguliu area located at Liaodong Peninsula,Eastern China.The natural faults/fractures based on field investigation combined with the discrete fracture network(DFN)generated by the MATLAB are used to represent the two-dimensional geological model.Numerical results show that early thermal breakthrough occurs at the production well caused by quick flow of cold water along the highly connected fractures.Suitable hydraulic fracturing treatments with proper injection rates,locations,etc.can efficiently hinder the thermal breakthrough time in the natural fracture system.Large well spacing helps the long-term operation of geothermal production,but it is highly dependent on the geometrical morphology of the fracture network.The enhancement of reservoir properties at the near-well regions can also increase the geothermal production efficiency.The results in this study can provide references to achieve a sustainable geothermal exploitation in fractured granitic geothermal reservoirs or hot dry rocks at depth.

Physico-mechanical properties of granite after cyclic thermal shock

Understanding rock mechanical behaviors after thermal shock is critically important for practical engineering application.In this context,physico-mechanical properties of Beishan granite,Gansu Province,China after cyclic thermal shock were studied using digital image correlation(DIC),acoustic emission(AE)monitoring,and microscopic observation.The results show that the peak strength and elastic modulus decreased gradually with increase in thermal shock cycle.However,the above two parameters showed no further changes after 10 thermal shock cycles.The loading stress ratio(i.e.the ratio of the current loading stress level to the peak stress in this state)corresponding to the occurrence of the uneven principal strain field and the local strain concentration zone on the surface of the granite specimen decreased with increase in thermal shock cycle.Three transformation forms of the standard deviation curves of the surface principal strain were found.For granite with fewer thermal shock cycles(e.g.no more than 2 cycles),the standard deviation curves exhibited approximately exponential growth in exponential form.With increase in thermal shock cycle,the S-shaped curve was dominant.After 10 thermal shock cycles,an approximate ladder-shaped curve was observed.It is displayed that AE activity was mainly concentrated around the peak strength zone of the granite specimen when the rock samples underwent fewer thermal shock cycles.With increase in thermal shock cycle,AE activity could occur at low loading stress levels.Microscopic observation further confirmed these scenarios,which showed that more microcracks were induced with increase in thermal shock cycle.The number of induced microcracks at the edge location of the granite specimen was significantly larger than that at the interior location.Finally,a continuum damage model was proposed to describe the damage evolution of the granite specimen after cyclic thermal shock during loading.

Influence of cooling speed on the physical and mechanical properties of granite in geothermal-related engineering

In deep-earth engineering,the high earth temperature can significantly affect the rock's mechanical properties,especially when the rock is cooled during the construction process.Accordingly,whether the cooling speed affects the mechanical and physical properties of rocks is worth to be investigated.The present study explored the influence of the cooling rate on the physical and chemical properties of granite heated at 25–800°C.The mechanical and physical properties involved in this study included uniaxial compression strength,peak strain,modulus,P-wave velocity,mass and volume,the change of which could reflect the sensitivity of granite to the cooling rate.Acoustic emission(AE)monitoring,microscopic observation,and X-ray diffraction(XRD)are used to analyze the underlying damage mechanism.It is found that more AE signals and large-scale cracks are accounted for based on the b-value method when the specimens are cooled by water.Furthermore,the microscopic observation by polarized light microscopy indicates that the density,opening degree,and connectivity of the cracks under water cooling mode are higher than that under natural cooling mode.In addition,the XRD illustrates that there is no obvious change in mineral content and diffraction angle at different temperatures,which confirms that the change of mechanical properties is not related to the chemical properties.The present conclusion can provide a perspective to assess the damage caused by different cooling methods to hot rocks.

Comparison of microwave- and thermal-assisted rock fragmentation methods at different temperatures and loading rates

Understanding the effects of microwave irradiation and thermal treatment on the dynamic compression and fragmentation properties of rocks is essential to quantify energy consumption in rock engineering.In this study,Fangshan granite(FG)specimens were exposed to microwave irradiation and heat treatment.The damage of FG specimens induced by these two methods was compared using X-ray CT scanning and ultrasonic wave method.The temperatures of FG after microwave irradiation and thermal treatment were effectively evaluated using a newly proposed technique.A novelty method for precisely determining the geometric features of fragments is developed to estimate the fragmentation energy.Thus,the dynamic uniaxial compressive strength(UCS),the dynamic fragmentation characteristics,and the fragmentation energy of FG after these two pretreatment methods can be reasonably compared.The noticeable distinction of loading rate effect on the dynamic UCS of FG between these two pretreatment methods is first observed.A relationship is established between the dynamic UCS and the damage induced by microwave irradiation and heat treatment.Moreover,fragmentation energy fan analysis is introduced to accurately compare the fragmentation properties of FG after two pretreatment methods in dynamic compression tests.

Macro and micro mechanics behavior of granite after heat treatment by cluster model in particle flow code

In this paper, a cluster model in particle flow code was used to simulate granite specimens after heat treatment under uniaxial compression. The results demonstrated that micro-cracks are randomly distributed in the specimen when the temperature is below 300?C, and have partial coalescence when the temperature is up to 450?C, then form macro-cracks when the temperature is above 600?C. There is more inter-granular cracking than intra-granular cracking, and their ratio increases with increasing temperature.The micro-cracks are almost constant when the temperature decreases from 900?C to room temperature, except for quartz α–β phase transition temperature(573?C). The fracture evolution process is obviously affected by these cracks, especially at 600–900?C. Elevated temperature leads to easily developed displacement between the grains, and the capacity to store strain energy becomes weaker, corresponding to the plasticity of granite after heat treatment.

Changes in the thermodynamic properties of alkaline granite after cyclic quenching following high temperature action

During the development of hot dry rock,the research on thermal fatigue damage caused by thermal shock of cold and heat cycles is the basis that ensures the long-term utilization of geothermal resources,but there are not enough relevant studies at present.Based on this,the thermal damage tests of granite at different temperatures(250,350,450°C)and quenching cycles(1,5,10,15 cycles)were carried out.Preliminary reveals the damage mechanism and heat transfer law of the quenching cycle effect on hot dry rock.The results show that with the increase of temperature and cycles,the uneven thermal expansion of minerals and the thermal shock caused by quenching promote the crack development of granite,resulting in the decrease of P-wave velocity,thermal conductivity and uniaxial compressive strength of granite.Meanwhile,the COMSOL was used to simulate the heat transfer of hot dry rock under different heat treatment conditions.It concluded that the increase in the number of quenching cycles reduced the heat transfer capacity of the granite,especially more than 10 quenching cycles,which also reflects that the thermal fatigue damage leads to a longer time for the temperature recovery of the hot dry rock mass.In addition,the three-dimensional nonlinear fitting relationship among thermal conductivity,temperature and cycle number was established for the first time,which can better reveal the change rule of thermal conductivity after quenching thermal fatigue effect of hot dry rock.The research results provide theoretical support for hot dry rock reservoir reconstruction and production efficiency evaluation.

Deterioration of equivalent thermal conductivity of granite subjected to heating-cooling treatment

Understanding the thermal conductivity of granite is critical for many geological and deep engineering applications.The heated granite was subjected to air-,water-,and liquid nitrogen(LN2-)coolings in this context.The transient hot-wire technique was used to determine the equivalent thermal conductivity(ETC)of the granite before and after treatment.The deterioration mechanism of ETC is analyzed from the meso-perspective.Finally,the numerical model is used to quantitatively study the impact of cooling rate on the microcrack propagation and heat conduction characteristics of granite.The results show that the ETC of granite is not only related to the heating temperature,but also affected by the cooling rate.The ETC of granite decreases nonlinearly with increasing heating temperature.A faster cooling rate causes a greater decrease in ETC at the same heating temperature.The higher the heating temperature,the stronger the influence of cooling rate on ETC.The main explanation for the decrease in ETC of granite is the increase in porosity and microcrack density produced by the formation and propagation of pore structure and microcracks during heating and cooling.Further analysis displays that the damage of granite at the heating stage is induced by the difference in thermal expansion and elastic properties of mineral particles.At the cooling stage,the faster cooling rate causes a higher temperature gradient,which in turn produces greater thermal stress.As a result,it not only causes new cracks in the granite,but also aggravates the damage at the heating stage,which induces a further decrease in the heat conduction performance of granite,and this scenario is more obvious at higher temperatures.

温度循环荷载下花岗岩微裂隙演化试验

花岗岩力学性能随环境温度的变化是岩石力学领域的热点问题,其微细观结构随温度的演化规律尚不清晰。基于现代化测试技术和实验设备设计了等幅值温度循环和峰值递增温度循环荷载,关注其作用下花岗岩微裂隙的衍生和扩展规律,并讨论了风化程度的影响。研究结果表明峰值温度比循环次数对裂隙网络发展的影响更大,峰值递增的温度循环可促进表面裂隙的衍生,而风化在一定程度上可减弱温度荷载的影响。本文研究可促进对温度作用下岩石力学性能演化的认知。

加热-冷却过程中花岗岩细观热破裂机制

由于高温试验设备的限制,在实验室中研究岩石真实热破裂规律通常需要依据冷却后试样的细微观结构观测结果来进行分析推断,无法获得热破裂的实时动态演化过程。为此,基于考虑温度和裂纹滑移效应的节理本构关系,构建花岗岩热力耦合UDEC晶粒模型,以深入探究加热和冷却过程中花岗岩的实时热破裂行为。研究发现,在加热状态下,花岗岩热诱导微裂纹在75℃左右开始萌生,随着温度的升高,微裂纹数量在α→β石英相变温度附近快速达到峰值,但微裂纹密度在600℃降温到25℃的冷却过程中并没有明显变化。虽然冷却效应引起的裂纹数量变化可以忽略不计,但会导致裂纹开度的增加或减少。在加热过程中,微裂纹的萌生主要是由于相邻晶粒的热膨胀不同导致局部应力累积造成的。而石英高温相变引起的细微观结构变化可以增强不同晶粒之间的相互作用,导致晶粒尺度上的压缩和剪切运动加剧,使得热应力裂纹继续变形拓展。在冷却过程中,由于加热过程中热破裂导致的细微观应力释放和冷却效应导致的不同矿物晶体收缩,使得微裂纹的数量虽然不变,但其形态却能发生较为明显的变化,从而使得冷却后花岗岩的宏观应力-应变行为受到很大影响。基于离散元数值模拟对花岗岩热力耦合试验结果作出了细微观阐释,揭示了加热和冷却过程中花岗岩的实时热破裂机制,进一步加深了对高温岩石热力耦合规律的理解。

基于非傅里叶定律的近场动力学热力耦合模型及花岗岩热损伤破裂模拟

研究岩石的热损伤破裂特征对于地热开采等工程具有重要意义。在传统常规态基近场动力学理论框架内,通过引入双相滞后(DPL)模型,提出了基于非傅里叶热传导定律推导得到的热力耦合模型。通过平板瞬态热传导问题及Lac du Bonnet(LdB)花岗岩的热损伤破裂试验对模型进行了验证。分析了温度梯度弛豫时间和热流弛豫时间对岩石热损伤破裂特征的影响。结果表明:近场动力学热力耦合模型模拟结果很好地反映了LdB花岗岩的热损伤破裂特征及温度分布的不连续性;温度梯度弛豫时间对热传导起促进作用,试件热损伤破裂程度随温度梯度弛豫时间的增加而增大,随热流弛豫时间的增加而减小。研究为深入理解岩石的热损伤破裂行为、优化地热能开采工程提供了有益的探索。

高温热冲击下花岗岩内一维热传导规律试验研究

热对岩石物理力学性质的劣化作用受岩石的结构、矿物组成及分布等多方面因素共同决定。为解决工程中存在的半无限大物体经历高温热冲击时其内部的一维热传导问题,通过设置高温热冲击试验,对热冲击过程中的温度场、升温速率、温度梯度场进行分析,并引入热冲击因子来定量表征高温热冲击过程中热对岩石的破坏程度,探讨热源温度及介质对花岗岩传热的影响,研究结果表明:不同冲击温度下花岗岩内温度变化均分为3个阶段:快速升温阶段、缓慢升温阶段、稳定阶段;由于花岗岩的非均质性,高温热冲击下花岗岩内温度场和温度梯度场分布均具有紊乱性,且温度梯度场紊乱程度高于温度场;高温热冲击过程中热冲击因子在花岗岩内的分布具有明显的非均质性,且其波峰具有动态移动的性质;100℃时,水相对硅油具有更大的对流换热系数,此状态下花岗岩内温度、升温速率、温度梯度均具有更大的峰值且更早进入稳定阶段。

冷热交替循环作用后花岗岩渗流特性及微观结构演化规律研究

我国深层地热资源分布广、储量大,具有广阔的开发利用前景。为了探究间歇注水地热开采条件下深部高温储层的渗流特性及演化规律,采用室内试验与微细观分析相结合的方法,对不同温度交替循环作用后的花岗岩开展了渗流试验,分析了试件在不同围压下渗透率随温度及循环次数的变化规律;结合显微薄片特征和CT扫描重构结果,研究了微观孔裂隙结构随温度及循环次数的演化过程。研究结果表明:(1)不同温度交替循环作用对花岗岩的渗透率存在较大影响,两种冷却方式下花岗岩渗透率随温度的升高逐渐增大,当温度超过400℃时渗透率急剧增大,且遇水冷却条件下的渗透率增幅明显大于自然冷却,遇水冷却循环10次后的参数变化更加显著。(2)应力状态对渗透率具有明显的影响,围压作用下试件内部孔裂隙结构闭合,不同温度交替循环作用后花岗岩的渗透率随着围压的增大呈递减趋势,随着渗透压的增加呈现逐渐增大的趋势。(3)高温-冷却循环作用下花岗岩内部微观孔裂隙逐渐发育,温度梯度应力造成矿物颗粒间的非均匀变形,同时在脱水、相变等物理化学反应的联合作用下产生沿晶裂纹、穿晶裂纹及颗粒剥落等劣化损伤,且随着循环次数的增加,裂纹数目、尺寸及连通程度进一步增大。研究结果可为深层干热岩地热开发及储留层建造提供理论支持和技术参考。

青海共和盆地花岗岩细观热损伤研究

【目的】花岗岩是干热岩地热能主要储藏的岩体之一,研究热及热冲击对花岗岩的损伤机制对于干热岩地热开采有一定的工程及理论意义。【方法】利用偏光显微镜分别对花岗岩从室温缓慢升高至600℃的全过程、在空气中自然冷却和在水中热冲击冷却至室温后的细观结构进行观察,并通过对视野中矿物面积和裂缝数量进行定量分析,来探究升温过程中及经不同冷却介质热冲击后花岗岩的损伤作用。【结果】结果表明:1)花岗岩在升温过程中矿物面积呈现随温度升高而增大的趋势;高温花岗岩经自然冷却后的矿物面积略大于热处理前,而水中热冲击后矿物面积略小于600℃状态下但显著大于热处理前。2)在升温过程中,视野内裂缝总体呈现小裂缝增多→小裂缝贯穿形成的大裂缝增多→大、小裂缝持续增多的规律,且300℃为小裂缝减少、大裂缝增多的临界温度。3)高温花岗岩在水中热冲击后,裂缝总数增加,其中0~100μm的裂缝显著增多;而空气中自然冷却后的花岗岩的裂缝总数减少,且0~100μm的裂缝显著减少,说明对冷却过程反应更敏感的是较短小的裂缝。4)通过对矿物收缩程度、裂纹数量变化的分析,发现高温花岗岩水中热冲击冷却造成的内部破裂更严重。

花岗岩侵位后的热应力时空演化及其影响因素

花岗岩与岩浆热液型矿床、油气成藏等有密切的成因关系。高温岩浆侵位到较冷的围岩中会形成岩浆热场和热应力,但热应力的大小和其影响范围尚缺乏系统研究。随着岩浆热耗散、与周围地层达到热平衡后,热应力会逐渐消失,因而数值模拟是定量研究岩浆热应力的常见方法之一。以往模拟岩浆热应力时往往采用岩石在常温下的线性热膨胀系数,但这与高温下岩石线性热膨胀系数存在较大差距。文章利用FLAC3D软件模拟花岗质岩浆侵位至上地壳范围内引起的热应力。求解物理方程包括热传导方程与线性热弹性本构方程,其中热场可通过温度差和线性热膨胀系数改变应力场,但应力场的变化不影响热场(即热场与应力场的单向耦合)。通过一系列数值模拟实验考察围岩岩性(花岗岩或碳酸盐岩)、杨氏模量、热学参数和岩浆侵位深度如何影响岩浆在上覆围岩产生的热应力。数值实验结果表明:岩石热传导系数通过传热快慢影响热应力的变化;围岩的杨氏模量越大,热应力也越大;由于花岗岩的平均杨氏模量大于碳酸盐岩,所以围岩为花岗岩时产生的热应力要高于碳酸盐岩;围岩无论是花岗岩还是碳酸盐岩,其在高温条件下的线性热膨胀系数比常温时高约1个数量级,产生的热应力最高可达100 MPa。花岗岩浆侵位后,围岩温度逐渐升高,对应的热应力不断增大;随着与岩浆房距离的增大,热应力不断减小,影响范围为岩浆房上方2 km以内;侵位深度浅的岩浆房冷却较快,其产生的热应力更有利于上覆围岩裂隙的形成和扩展。综合数值模拟结果可知,岩浆侵位所产生的热应力可影响岩体2 km内的应力场,这一局部存在且短瞬的热应力促使围岩破裂,为热液流体成矿提供运移通道或容矿空间。

珠江三角洲与周边典型地区岩石热物性及其地热效应的比较研究

珠江三角洲位于华夏板块南部,虽然已发现多个水热型地热田,但地热研究仍然较为薄弱.岩石热物性研究是地热研究中最为基础和重要的工作之一.本研究采集并测量了珠江三角洲与周边典型地区100块地表岩石的密度、热导率、热扩散率,以及50块岩浆岩的U、Th、K_(2)O含量,并分别计算了体积热容和放射性生热率.实测结果表明,碎屑岩中细砂岩的热导率最高(3.94±0.92 W·(m·K)^(-1)),页岩的热导率最低(2.68±0.55 W·(m·K)^(-1)).岩石热导率和热扩散率具有明显的正相关性.结合地层厚度建立了地层热物性柱,其中古近系的热导率最低,地层热物性与沉积环境有关.岩浆岩中玄武岩的热导率最低(2.17±0.13 W·(m·K)^(-1)),花岗岩平均热导率为3.87±0.59 W·(m·K)^(-1).花岗岩放射性生热率在0.36~14.23μW·m^(-3)之间,平均值为5.23±3.03μW·m^(-3),属于高产热花岗岩.结合前人对研究区岩石放射性元素含量的测试结果,我们发现,相对于K_(2)O,U、Th与生热率具有更强的相关性,并对产热的贡献更高.相对于花岗岩,玄武岩的生热率较低,K_(2)O对产热的贡献较高.新的资料为区域热流的确定和地热资源评价提供了新的视角.模拟和计算结果表明,三水盆地沉积层能对深部热量起到聚集和保存的作用,并在基底附近形成高温区(>150℃);上地壳中花岗岩体产生的热流超过45 mW·m^(-2),占地表热流的一半以上.盆地和花岗岩体均具有形成高温地热资源的地质条件.此外,酸性岩浆岩放射性生热率随时间逐渐降低的特征与幔源基性岩浆的混合作用有关.