本文選題：地下管道 + 滲漏��； 參考：《鄭州大學(xué)》2017年碩士論文

【摘要】：近年來國內(nèi)外城市路面塌陷事故頻發(fā),造成了人們生命和財(cái)產(chǎn)的巨大損失。在所有路面塌陷事故的成因中,管道破裂滲漏所造成的影響占有較大的比重,因此對地下管道滲漏引起的路面塌陷機(jī)理進(jìn)行分析與研究,對保護(hù)人們?nèi)松戆踩蜏p少財(cái)產(chǎn)損失具有重要意義。本文通過滲流理論、室內(nèi)模型試驗(yàn)、數(shù)值模擬等方法對管道破損滲漏導(dǎo)致的路面塌陷機(jī)理及塌陷影響因素進(jìn)行了研究。(1)針對管周土體兩種不同的破壞形式,推導(dǎo)了地下水內(nèi)滲破壞管周土?xí)r的臨界地下水位降幅和臨界地下水流速,管周土體沖蝕破壞時管道內(nèi)水體的臨界滲流速度。(2)推導(dǎo)了路面塌陷前地下空洞的臨界跨徑與上覆土層的厚度、土的粘聚力、內(nèi)摩擦角、容重、外部荷載等之間的關(guān)系。(3)通過室內(nèi)模型試驗(yàn)得到地下水內(nèi)滲破損管道的地下空洞形態(tài)為圓錐柱形,管內(nèi)水體沖蝕管周土體的地下空洞形態(tài)為橢球形。并研究了在不同的管道破損口形式和大小時,地下空洞形態(tài)的發(fā)展變化。(4)通過FLAC3D數(shù)值模擬,認(rèn)為對于外滲空洞塌陷,在5m上覆土層厚度時,導(dǎo)致空洞塌陷的臨界跨徑為6m。在3m空洞跨徑時,導(dǎo)致空洞塌陷的臨界上覆土層厚度為4m。而土體的粘聚力和內(nèi)摩擦角的減小導(dǎo)致土體強(qiáng)度的降低,增大了外滲地下空洞的不穩(wěn)定性,當(dāng)土的粘聚力為13kPa和內(nèi)摩擦角為14°時,地下空洞將處于失穩(wěn)狀態(tài)。(5)通過FLAC3D數(shù)值模擬,認(rèn)為對于內(nèi)滲空洞塌陷,在5m上覆土層厚度時,導(dǎo)致空洞塌陷的臨界跨徑為4m。在4m空洞跨徑時,導(dǎo)致空洞塌陷的臨界上覆土層厚度為6m。而土體的粘聚力和內(nèi)摩擦角的減小導(dǎo)致土體強(qiáng)度的降低,也增大了內(nèi)滲地下空洞的不穩(wěn)定性,當(dāng)土的粘聚力為10kPa和內(nèi)摩擦角為14°時,地下空洞將處于失穩(wěn)狀態(tài)。
[Abstract]:In recent years, the frequent accidents of urban pavement collapse at home and abroad have caused great loss of people's lives and property. Among all the causes of pavement collapse accidents, the influence caused by pipeline rupture and leakage occupies a large proportion, so the mechanism of pavement collapse caused by underground pipeline leakage is analyzed and studied. It is of great significance to protect people's personal safety and reduce the loss of property. In this paper, seepage theory, laboratory model test and numerical simulation are used to study the mechanism of pavement collapse caused by pipe breakage and leakage and its influencing factors. (1) two different failure forms of soil around pipe are studied. The decrease of critical groundwater level and the critical velocity of groundwater are derived. The critical seepage velocity of the water body in the pipeline is obtained when the soil around the pipe is eroded. (2) the critical span of the underground cavity before the pavement collapse and the thickness of the overlying soil layer, the cohesive force of the soil, the angle of internal friction, the bulk density, are derived. (3) through the laboratory model test, the underground cavity shape of the damaged underground water seepage pipeline is conical column shape, and the underground cavity shape of the soil around the pipe is ellipsoidal. At the same time, the development and change of underground cavities are studied with different types and sizes of damaged pipes. (4) through FLAC3D numerical simulation, it is considered that the critical span of cavities collapse is 6 m when the thickness of overlying soil is 5 m. At the span of 3m cavities, the critical overlying layer thickness of cavities collapsing is 4 m. However, the decrease of cohesive force and internal friction angle leads to the decrease of soil strength, which increases the instability of underground cavity. When the cohesive force of soil is 13 KPA and the angle of internal friction is 14 擄, the underground cavity will be unstable. (5) the numerical simulation of FLAC3D shows that the underground cavity will be unstable when the cohesive force is 13 KPA and the angle of internal friction is 14 擄. It is considered that the critical span of cavities collapse is 4 m when the thickness of overlying soil is 5 m. When the cavities span is 4 m, the critical overlying layer thickness of cavities collapsing is 6 m. The decrease of cohesive force and internal friction angle leads to the decrease of soil strength and increases the instability of underground cavity. When the cohesive force of soil is 10 KPA and the angle of internal friction is 14 擄, the underground cavity will be unstable.
【學(xué)位授予單位】：鄭州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TU990.3;U418.6

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